Well it's all over the Internet now but the official announcement of Beta 2 of the XNA Game Studio Express is at the XNA Blog. There are a bunch of changes, some of them added features but some of them may break code developed with Beta 1, so you will want to read all about it at this post on the XNA Blog as well.
You can get the latest bits here. Download them and have some fun. Oh that reminds me, my co-worker Krishna is looking for some good sample projects to highlight. Check out his blog for more information about that and other news. In fact he leaked news of the beta release before it was official. But don't tell anyone.