Ubuntu 6.10 is pretty old as versions go... I've actually got 9.04 (Jaunty Jackalope) installed on a Wallstreet and a Pismo.
The trick, in both cases, was to use the Alternate CD (not the Live one). The Wallstreet was surprisingly easy once I got the right set of BootX options selected. The Pismo was actually a bit harder as I had to manually edit the xorg.conf file.
Getting back to the original topic, the Wallstreet multiboots Panther, 9.2.2, and Ubuntu 9.04. The Pismo multiboots Tiger, 9.2.2 and Ubuntu 9.04, though I want to try and install NetBSD to the spare partition.
John