These are possibly my worst written notes ever below. Beware!
Xen was remarkably easy to install on Lenny. I just installed the latest xen kernel
(2.6.26-2-xen-686) and xen-hypervisor-3.2-1-i386 xen-utils (3.0?), also these bridge-utils
iproute sysfsutils libc6-xen xen-tools
Made sure these were in /etc/xen/xend-config.sxp
(network-script network-bridge)<br>
(vif-script vif-bridge)<br>
/etc/xen-tools/xen-tools.conf was basically this:
dir = /opt/xen #mkdir'd this first
install-method = debootstrap