OSGI Background Knowledge
From BUG Wiki
This page provides links and information about the OSGI Framework.
OSGi Wikipedia Entry A very high level view of the OSGi alliance and framework
Introduction to OSGi IBM Education presentation on OSGi Framework (Equinox Specific)
OSGi Service Platform White Paper A PDF document describing the architecture of OSGi.
OSGi in Practice A free book documenting on OSGi implementation. It is currently not completed yet. (Thanks to akravets in the forums)
Concierge is an implementation of the OSGi framework. It's focus is on compactness and specially designed to run on mobiles and embedded devices.