ActiveMQ implements a REST-ful API to messaging which allows any web capable device to publish or consume messages using a regular HTTP POST or GET.
(ActiveMQ is an open source, Apache 2.0 licenced Message Broker and JMS 1.1 implementation.)
I had done a servlet just like this (probably not nearly as professional) and posted it over on SourceForge http://sourceforge.net/projects/destiny. It's very gratifying to see someone else attempt the same thing. Next, I'd like to see SMTP and NNTP smoothed over and made transparent by some decent HTTP gateways - oh wait, isn't Google doing that?