[root@Kalisto ~]$ pacman -Qs virtualbox
local/virtualbox-modules 3.0.0-1
    Kernel modules for VirtualBox (vboxdrv)
local/virtualbox-ose 3.0.0-1
    Powerful x86 virtualization for enterprise as well as home use (Open Source Edition)
local/virtualbox-ose-additions 3.0.0-1
    Guest Additions for VirtualBox (Open Source Edition)
local/virtualbox-ose-additions-modules 3.0.0-1
    Kernel modules for VirtualBox Guest Additions

root@Kalisto ~]# lsmod | grep vb
vboxdrv               134792  0

[root@Kalisto ~]# ls -l /lib/modules/2.6.30-ARCH/misc/vbox*
-rw-r--r-- 1 root root  77378 2009-07-07 12:57 /lib/modules/2.6.30-ARCH/misc/vboxadd.ko
-rw-r--r-- 1 root root 152044 2009-07-06 22:29 /lib/modules/2.6.30-ARCH/misc/vboxdrv.ko
-rw-r--r-- 1 root root  98644 2009-07-06 22:29 /lib/modules/2.6.30-ARCH/misc/vboxnetadp.ko
-rw-r--r-- 1 root root 108510 2009-07-06 22:29 /lib/modules/2.6.30-ARCH/misc/vboxnetflt.ko
-rw-r--r-- 1 root root  63295 2009-07-07 12:57 /lib/modules/2.6.30-ARCH/misc/vboxvfs.ko

[root@Kalisto ~]# uname -a
Linux Kalisto 2.6.30-ARCH #1 SMP PREEMPT Sat Jul 4 11:13:08 UTC 2009 i686 AMD Athlon(tm) Processor AuthenticAMD GNU/Linux

[root@Kalisto ~]# modprobe vboxadd
FATAL: Error inserting vboxadd (/lib/modules/2.6.30-ARCH/misc/vboxadd.ko): No such device

[root@Kalisto ~]# modprobe vboxvfs
FATAL: Error inserting vboxvfs (/lib/modules/2.6.30-ARCH/misc/vboxvfs.ko): No such device