Enterprise Java Community: Modularizing Existing Web Applications With OSGi: A Migration Path to OSGi
http://www.theserverside.com/tt/articles/article.tss?l=MigratingPathToOSGi
This article takes you through 12 easy steps to understand how OSGi bundles can be used within an existing classic WAR application. Prior experience with Eclipse Web Tools (Tomcat runtime and launcher) is recommended. The code referred to in this article is available for download here [1].A Recap on OSGi - Why and How? | Eclipse Zone
Links to several OSGi articles for introduction
Bunch-O-Links to OSGI stuff