[CentOS] Booting CentOS 6 in VirtualBox on Ubuntu

I trying to try out CentOS 6 in an Oracle VirtualBox running on
Ubuntu. Has anyone been able to get this configuration working?

When I try to boot the "Live" ISO it starts to do the countdown but
when it reaches zero it gets stuck - nothing else happens. No error
messages and since the install never really gets going, no logs.

I've checked the mailing list archive back a few months, but I've not
seen anything related.

Cheers,

Cliff