The goal of PDE Build is to facilitate the automation of plug-in build processes. Essentially, PDE Build produces Ant scripts based on development-time information provided by, for example, the plugin.xml and build.properties files. The generated Ant scripts, can fetch the relevant projects from a CVS repository, build jars, Javadoc, source zips, put everything together in a format ready to ship and send it out to a remote location (e.g., a local network or a downloads server).
For more detailed information, check out the Development Resources.
If you are interested in participating in the development of the PDE Build component, check out the developer's mailing list: pde-build-dev@eclipse.org. Chat with people there about your problems and interests, and find out what you can do to help.
