Thanks to the hard work of a whole host of developers at The Genome Center, especially Scott Smith and Tony Brummett, UR, the class framework and object-relational mapping (ORM) layer we developed and use at The Genome Center, has been released on CPAN (actually, I am a little late announcing this, Scott has already uploaded version 0.3). UR is the foundation of the analysis pipelines I presented at the Biology of Genomes meeting at Cold Spring Harbor and the software I will be presenting at OSCON in July. As the list of modules indicate, it is quite a piece of software. It is able to interface with multiple databases simultaneously, handling cross-database joins and transactions while caching information in memory for impressive performance enhancements. If you need something more scalable and powerful than the ORM's available, i.e., you need an enterprise ORM, you should have a look. For an introduction to using UR in your environment, see the fine manual. Just like Perl, UR is released under a dual license, Artistic and GPL; you choose which one to use.
Update: Updated links to latest released version (0.6).