The RSS feed from PHP iCalendar is working quite nicely. It's actually quite a bit more useful then the calendar itself, because (assuming a decent RSS reader), you should see changes as they happen, rather then a monolithic block of 100+ events.
In fact, this is starting to look really useful. If you're interested in knowing when authors are visiting the Seattle area for book signings and talks, then subscribe to the feed(s).
When I have time, I'm probably going to start generating the RSS myself, rather then using PHP iCalendar, partly to get a better feel for RSS, and partly so I can start including better filtering options in the future.