Ant is composed of a primary project, described principally on the AntProjectPages, as well as a couple of hosted projects. You can browse through their source code by following these links.
the svn repositories contains references to the currently active modules of the ant project.
the ant-antidote CVS module contains source code for a GUI application called Antidote, which is intended for editing Ant build files. Because antidote was retired on 2005-04-04 the code is no longer maintainded and only available in the archive.