I have been playing with the new features of BizTalk 2009 and have been finding a few bugs. But some of what is available with this release is awesome. For example, due to Visual Studio 2008 integration you can reference a WCF Service library from your BizTalk project. You can also reference a project that uses LINQ so will be able to use LINQ indirectly in a BizTalk map. Another cool thing is that you can reference a WF library from your BizTalk project. This makes it possible to call a WF method directly from BizTalk and potentially move logic over to a WF process from BizTalk. I have not tried running a workflow from the BizTalk host but that will be the next thing to try. I have not seen any new BizTalk orchestration shapes for calling WF activities or workflows either.
The new UDDI functionality included with the BizTalk 2009 beta is a little buggy at this point but the functionality seems to be a big step forward. More details on this soon.
Lots of the wish list ideas I have had for where BizTalk could be going are things I am testing right now. Check back here as I find new features as part of the beta.