Biztalk 2006 R2 was supposed to be out yesterday. However, the official site
did not have a link to it. I have found the R2 at this other url:
you will find the url for the R2 on the right hand side. Click on it and that will take you to the connect home page. You will need to log in with your Microsoft Passport to be able to see your connections.
If you have not applied for the R2 program, scroll to the bottom and apply. After you apply you will be able to see the download screen (see below).
Will post more after I *play* with it… ;)