I noticed with not too much fan fare that BizTalk 2010 has finally been released, a few days earlier than expected, we were expecting end of this month, however we got it in on the 27th.
You can now download the Developer edition for free, there is no license required or cost involved with using the developer edition.
It works quite nicely with Visual Studio 2010, and comes complete with all the adapters required.
You can download the evaluation version here: Evaluation Version
Or the Developer Version here: Developer Edition
You may not see it on MSDN as yet for