WF hosting in BizTalk 2006? Sure!
Today was announced at TechEd 2007 the availability of a new tool to host WF workflows into BizTalk Server 2006. Sounds a good idea and confirms, like in this post of Paul Andrew, that WF will have a main role in future releases of BizTalk Server.
Many times, when I teach WF, people ask me what about BizTalk overlapping. I always answer that BizTalk Server is an application server to orchestrate messaging solutions, while WF is a base framework to build your own workflow solutions, but I also admit that a WF based BizTalk could be a good solutions to have a "zero-implementation-cost" hosting solution for real and scalable workflows defined with WF.