While I was still an Microsoft MVP and a Microsoft Regional Director, one of the things I have always requested is to have Windows Communication Foundation (WCF, previously - Indigo) run in the Compact Framework to enable ease of use of WS-Security Specifications in distributed (W3C) SOAP communications.
I mean, really - even Web Services Enhancements (WSE) did not work at the Compact Framework level. One of my friends and a really technically-brillant guy, Casey Chesnut cooked something up to enable us to use secured communications on the compact framework (which I used).
Now, I guess the CF in WCF means it can work in the Compact Framework now, finally. This is a good read to show whats coming up. For more, you would have to attend MEDC 2007 in Vegas later this month.