Microsoft released the BizTalk ESB Toolkit 2.0, formerly known as the ESB Guidance 2.0. This toolkit extends BizTalk Server 2009 (download) capabilities to support a loosely coupled and dynamic messaging architecture. It functions as middleware that provides tools for rapid mediation between services and their consumers. Enabling maximum flexibility at run time, the BizTalk ESB Toolkit 2.0 simplifies composition of service endpoints without “hard-wiring” them and also provides management of service interactions at enterprise scale.

Download: BizTalk ESB Toolkit 2.0 | Documentation