Bidirectional-streams Over Synchronous HTTP (BOSH) (XEP-0124)

Known server implementations:


 * ejabberd
 * Openfire
 * Tigase (on the way)
 * PunJab (a Python-based connection manager for any XMPP server)

Matthew Wild added BOSH support to the gloox C++ library as part of Google Summer of Code 2007.

Tomas Karasek is adding BOSH support to the Gajim client as part of Google Summer of Code 2008. He has a blog post about various BOSH implementations here.