Hello,
I recently came across the first BitTorrent client for Java ME, called MobTorrent. You can find it and its source on this page. Although it still has some bugs like the OutOfMemory-Exceptions that occur sometimes, it is a very good start for implementing the Bittorrent protocol based on the Java ME platform. I wonder, when the first Gnutella client for Java ME will be released :-)
Best
makube
