I've been looking into windows workflow foundation..

I couldn't help noticing that WWF combined with WCF was looking a lot like a biztalk service with orchestrations. So thought I'd better get an understanding about how the two relate to one another.

BTS is an enterprise level server with all sorts of audit, monitoring, failsafe, mature tools ('n stuff) built in. WWF is a more flexible alternative to orchestations (looks like next version of BTS will be using WF + WCF instead of orchestrations and adapters).

A nice 'takeaway' comment people seem to be saying is that Biztalk is the choice for implementing workflow across applications. WWF is the better choice for handling workflow within you applications. Well I'll remember that much at least!