Literally for squeeze,
apt-get install qemu-kvm libvirt-bin
To manage vm’s as a normal user, add that user to the libvirt group.
More on KVM here.
Then you can use virsh to manage vm’s on the command line! But since that can be a pain, I highly recommend using virt-manager (a gnome gui utility) or some other gui (web/desktop) utility which can connect to libvirt remotely and manage your KVM Server.
To enable libvirt to listen for incoming connections:
Then in /etc/libvirt/libvirtd.conf:
listen_tls = 0
listen_tcp = 1
Now restart libvirt (service libvirt-bin restart) and use your remote vm manager applicaton to log onto the server and do stuffs! Moar on setting up libvirt here.
As I do more with KVM and other guis, i will fill you in!