A couple of cool announcements about free dev tools specifically for casual games. First, casual games giant Pop Cap has released their developer tools for general use. It's a VC++ framework so be prepared for it, but potentially a great resource; developing on the same framework as Bejeweled and Zuma can't be all bad.

Second, Three Rings Designs (of Puzzle Pirates fame) have announced the launch of Game Gardens, an opensource game development toolkit for multiplayer games. They'll even host your multiplayer games there, which is very cool. Game Gardens appears to be Java-based, and there are also some docs and samples available.