See what Google has to say.
Plans has an entry on Freshmeat, where some folks have posted comments.
TotalChoice Hosting has detailed
instructions for running Plans on their servers.
(Disclaimer: planscalendar.com has no business relationship with TotalChoice Hosting.)
(Disclaimer-er: In fact, planscalendar.com has no business relationship at all. The ".com" is sort of misleading.)