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).
If you are interested in participating in the development of the PDE Build component, check out the developer's mailing list: firstname.lastname@example.org. Chat with people there about your problems and interests, and find out what you can do to help.