MSMQ has been available on Windows CE and Windows Mobile for a while now. It was quite interesting, but I found the implementation as recently as PocketPC 2003 too difficult to use.
That said, I've been using it on my new Windows Mobile 5.0 device and things have improved a lot, but I had been under the impression that the HTTP transport would not be forthcoming because of limitations in the XML libraries on the ROM.
Well,
in Marcus Perryman's blog today, he announcesthat in fact it wasnt included because of a bug, and that a bug fix is actually coming soon!
This is really going to help sell Windows Mobile further to the enterprise.