William,
Take a look at http://dev.openacs.org/about/what-is-openacs. It has a link to http://dev.openacs.org/packages/package-list which is a list of the packages available on that instance of OpenACS (almost all of the packages in CVS right now).
Welcome to the community. The bboards here are a friendly place to ask questions, so don't be shy. Our not-so-great documentation (available in your OpenACS instance at /doc) should be of great help too.
