http://www.linux-kvm.org - The real 'home' page for Linux Kernel based Virtual Machine
http://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine - The Wikipedia entry
Other popular KVM wikis:
http://virt.kernelnewbies.org/KVM
http://wiki.debian.org/KVM
https://wiki.ubuntu.com/kvm
https://help.ubuntu.com/community/KVM
http://en.gentoo-wiki.com/wiki/KVM