I've installed SL6 Alpha 1 as a VirtualBox (Version 3.2.12) guest on an
XP SP3 host. It seems to run well with 512 MB of guest memory; and
basic guest-additions features like shared folders and full-screen mode
seem to work.
Don't know if this is useful feedback at the alpha stage, but for
whatever its worth: the dkms and yum-conf-epel packages don't seem to be
in the repo.