Geniusql
Hrm… Geniusql seems to be getting quite a bit of buzz lately:
Geniusql is a public domain, low-level Object-Relational Mapper for Python applications. If you’re familiar with Martin Fowler’s work, you can think of Geniusql as providing a Data Source layer. It primarily uses a generic Table Data Gateway architecture (as opposed to the more tightly-coupled Active Record architecture recently popularized by Ruby On Rails and Django).
I haven’t personally used it (yet).