We use Google's Calendar as part of our church web page. It's easy to keep up to date and we don't have to install any special calendar software on our server. It even has an extremely sophisticated XML feed. OK, the feed is considerably shorter, if you tweak the call a bit, using Google's published parameters. You can use this feed in an RSS aggregator, informing your readers about what's happening in the near future. But this might not be exactly what you want.
This turns out to be relatively easy to do, if you know the trick,