Brian has been busy looking at the integration capabilities of BizTalk, the ESB Toolkit 2.0 and the Windows Azure service bus. There are two webcasts looking at different aspects of this:
Extending the Reach: Using a BizTalk Dynamic Send port to send to Windows Azure platform AppFabric Service Bus
Extending the Reach: Using a BizTalk ESB Off-ramp to send to Windows Azure platform AppFabric Service Bus