Thanks to Tomas Cohen, Koyami, and Shadower SC at the Koha Wiki, I now have a working instance of the Koha ILS on one of my scratchboxes. ("ILS" is short for "Integrated Library System".) While there's a couple formatting issues (bad wiki markup?), their article includes 99% of the info needed to get an instance up and running from source.
I was having a lot of trouble with getting the Koha VM running under ESXi 4.1. Frustration set in and I resorted to building it from source. Other than adjusting usernames, database names, and tweaking Apache a few times, their article works pretty well for an install on a paravirtualized Ubuntu Server 10.4.
Notes in the wiki shortly... Still need to wade through the tutorials. Then there's a number of extensions that "need playing with".