apt-cache policy virtualbox && apt-cache depends virtualbox
virtualbox:
  Installed: 1.5.6-28266_Ubuntu_gutsy
  Candidate: 1.5.6-28266_Ubuntu_gutsy
  Version table:
 *** 1.5.6-28266_Ubuntu_gutsy 0
        500 http://www.virtualbox.org gutsy/non-free Packages
        100 /var/lib/dpkg/status
virtualbox
  Depends: libc6
  Depends: libgcc1
  Depends: libglib2.0-0
  Depends: libice6
  Depends: libidl0
  Depends: libpng12-0
  Depends: libqt3-mt
  Depends: libsdl1.2debian
  Depends: libsm6
  Depends: libssl0.9.8
  Depends: libstdc++6
  Depends: libx11-6
  Depends: libxalan110
  Depends: libxcursor1
  Depends: libxerces27
  Depends: libxext6
  Depends: libxt6
  Depends: zlib1g
 |Depends: debconf
  Depends: <debconf-2.0>
    cdebconf
    debconf
  Depends: psmisc
  Depends: adduser
 |PreDepends: debconf
  PreDepends: <debconf-2.0>
    cdebconf
    debconf
  Recommends: libasound2
  Recommends: libpulse0
  Recommends: libsdl-ttf2.0-0
  Recommends: <linux-headers>
    linux-headers-2.6.24-11
    linux-headers-2.6.24-11-386
    linux-headers-2.6.24-11-generic
    linux-headers-2.6.24-11-rt
    linux-headers-2.6.24-11-server
    linux-headers-2.6.24-11-virtual
    linux-headers-2.6.24-11-xen
  Recommends: gcc
  Recommends: make
  Recommends: binutils
  Recommends: bridge-utils
  Recommends: uml-utilities
  Recommends: libhal1
  Recommends: <pdf-viewer>
    evince
    evince-gtk
    gv
    kghostview
    kpdf
    viewpdf.app
    xpdf-reader
    xpdf-utils