[root@cohan yum.repos.d]# pwd
/etc/yum.repos.d
[root@cohan yum.repos.d]# cat CentOS-Base.repo
# CentOS-Base.repo
#
# This file uses a new mirrorlist system developed by Lance Davis for CentOS.
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
enabled=1
exclude=php* kernel* postfix*
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4

#released updates
[update]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
enabled=1
exclude=php* kernel* postfix*
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4

#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever - Addons
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=addons
baseurl=http://mirror.centos.org/centos/$releasever/addons/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4

[root@cohan yum.repos.d]# yum upgrade
Setting up Upgrade Process
Setting up repositories
Reading repository metadata in from local files
Excluding Packages from CentOS-4 - Updates
Finished
Excluding Packages from CentOS-4 - Base
Finished
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Package mozilla-mail.x86_64 37:1.7.13-1.4.1.centos4 set to be updated
---> Package kernel-devel.x86_64 0:2.6.9-34.107.plus.c4 set to be installed
---> Package ruby-tcltk.x86_64 0:1.8.1-7.EL4.3 set to be updated
---> Package squirrelmail.noarch 0:1.4.6-5.el4.centos4 set to be updated
---> Package postfix.x86_64 2:2.1.5-4.2.RHEL4.mysql.centos4 set to be updated
---> Package xorg-x11-Mesa-libGLU.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-xfs.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-Mesa-libGLU.i386 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package mozilla.x86_64 37:1.7.13-1.4.1.centos4 set to be updated
---> Package xorg-x11-devel.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package tkinter.x86_64 0:2.3.4-14.2 set to be updated
---> Package xorg-x11-font-utils.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package rdesktop.x86_64 0:1.4.1-1.EL4plus set to be updated
---> Package devhelp-devel.x86_64 0:0.9.2-2.4.8 set to be updated
---> Package openmotif21.i386 0:2.1.30-11.RHEL4.5 set to be updated
---> Package xorg-x11-Xnest.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-deprecated-libs.i386 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-Mesa-libGL.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-tools.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-devel.i386 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-deprecated-libs.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package postfix-pflogsumm.x86_64 2:2.1.5-4.2.RHEL4.mysql.centos4 set to be updated
---> Package xorg-x11.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package kernel-largesmp-devel.x86_64 0:2.6.9-34.107.plus.c4 set to be updated
---> Package firefox.x86_64 0:1.5.0.2-3.c4.centos set to be updated
---> Package openmotif-devel.x86_64 0:2.2.3-10.RHEL4.1 set to be updated
---> Package mozilla-devel.x86_64 37:1.7.13-1.4.1.centos4 set to be updated
---> Package kernel-doc.noarch 0:2.6.9-34.106.unsupported set to be updated
---> Package dia.x86_64 1:0.94-5.7.1 set to be updated
---> Package xorg-x11-twm.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package thunderbird.x86_64 0:1.0.8-1.4.1.centos4 set to be updated
---> Package devhelp.x86_64 0:0.9.2-2.4.8 set to be updated
---> Package openmotif.i386 0:2.2.3-10.RHEL4.1 set to be updated
---> Package xorg-x11-Xdmx.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-xdm.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package openmotif.x86_64 0:2.2.3-10.RHEL4.1 set to be updated
---> Package mozilla-dom-inspector.x86_64 37:1.7.13-1.4.1.centos4 set to be updated
---> Package xorg-x11-Mesa-libGL.i386 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-libs.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package kernel-smp-devel.x86_64 0:2.6.9-34.107.plus.c4 set to be updated
---> Package xorg-x11-xauth.x86_64 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package xorg-x11-libs.i386 0:6.8.2-1.EL.13.25.1 set to be updated
---> Package kernel.x86_64 0:2.6.9-34.107.plus.c4 set to be installed
---> Package kdegraphics.x86_64 7:3.3.1-3.9 set to be updated
--> Running transaction check
--> Processing Dependency: tkinter = 2.3.4-14.1 for package: python-tools
--> Processing Dependency: kdegraphics = 7:3.3.1-3.7 for package: kdegraphics-devel
--> Processing Dependency: mozilla = 37:1.7.12-1.4.2.centos4 for package: mozilla-js-debugger
--> Processing Dependency: xorg-x11-devel = 6.8.2-1.EL.13.25 for package: xorg-x11-deprecated-libs-devel
--> Processing Dependency: xorg-x11 = 6.8.2-1.EL.13.25 for package: xorg-x11-Xvfb
--> Processing Dependency: mozilla = 37:1.7.12-1.4.2.centos4 for package: mozilla-chat
--> Processing Dependency: xorg-x11-deprecated-libs = 6.8.2-1.EL.13.25 for package: xorg-x11-deprecated-libs-devel
--> Finished Dependency Resolution
Error: Missing Dependency: tkinter = 2.3.4-14.1 is needed by package python-tools
Error: Missing Dependency: kdegraphics = 7:3.3.1-3.7 is needed by package kdegraphics-devel
Error: Missing Dependency: mozilla = 37:1.7.12-1.4.2.centos4 is needed by package mozilla-js-debugger
Error: Missing Dependency: xorg-x11-devel = 6.8.2-1.EL.13.25 is needed by package xorg-x11-deprecated-libs-devel
Error: Missing Dependency: xorg-x11 = 6.8.2-1.EL.13.25 is needed by package xorg-x11-Xvfb
Error: Missing Dependency: mozilla = 37:1.7.12-1.4.2.centos4 is needed by package mozilla-chat
Error: Missing Dependency: xorg-x11-deprecated-libs = 6.8.2-1.EL.13.25 is needed by package xorg-x11-deprecated-libs-devel

Thats it, thanks in advance. It looks like I could update some software but the unavailable deps stop it?