Interchange is the open source alternative to commercial e-commerce
servers and "best of breed" application server/component applications.
Interchange is one of the most powerful tools available to automate and
database-enable your web site or build online applications. It's also
one of the easiest tools to learn, plus it's open source, making it the
most open and least expensive solution to implement.

For some documentation and resources for it have a look at
  http://www.interchange.rtfm.info/

WWW: http://www.icdevgroup.org/