Thomas wrote in to oss4lib-list about eprints.org [1] and its promise of a free code release [2]. At the site you'll see that this is a generic successor to the CogPrints [3] codebase, and is intended to be fully Open Archives [4]-savvy. This is a Good Thing(tm)...
Links:
[1] http://www.eprints.org/
[2] http://www.eprints.org/software.html
[3] http://cogprints.soton.ac.uk/
[4] http://www.openarchives.org/