It appears beta 2 of BizTalk 2006 has been released a day earlier than I had expected. This is certainly a bonus for me, as I was too busy to install any of the releases since beta 1 and was waiting for this release before going through the installation process again.
The download is available in the usual location at http://beta.microsoft.com - you obviously have to be enrolled on the beta in order to obtain it. Along with this release Microsoft are also making available the beta versions of the recently announced Microsoft Line of Business Adapters for Siebel, Oracle, PeopleSoft, J.D. Edwards, and Tibco. The Beta-2 Known Issues and Installation Guide is available here.
It looks like I now have a few days worth of installations to undertake...