Curious about BizTalk Server 2006 features and functionality?  A preview of the final product documentation in .chm format is available here: http://blogs.msdn.com/luke/archive/2006/02/03/524534.aspx

Check out the performance content under the topic "Planning for Sustained Performance".  Under this topic, we provide maximum sustainable throughput numbers with and without tracking, plus tips and tricks, scaling guidence, project planning, throttling, and more!