Although this tool is not new, I blog about it because it is a must-have for every BizTalk developer:

The tool is called UK SDC BizTalk 2006 Documenter (you can download it here) and builds documentation of your BizTalk application(s). It uses reflection to find all information, therefore the BizTalk application(s) you want to document need(s) to be deployed.
One cool feature is the ability to create JPG’s for orchestrations.