I presented at the utah python user group last night. I gave an introduction to the PyDO2 ORM tool as well as the python DB API and psycopg. Most readers are probably most interested in the pydo2 section. Here's the slides: http://utahpython.org/data/python-and-databases.pdf.
I briefly mentioned SqlAlchemy in the context of, "here's some stuff that SqlAlchemy does that pretty much nobody else can," but didn't have time to cover TWO ORM tools. It's worth having a look at though if you've reached the limits of what pydo2 et al can do.