I've seen a number of postgresql modules for python like pygresql, pypgsql, psyco. Most of them are Python DB API 2.0 compliant, some are not being actively developed anymore.
Which module do you recommend? Why?
psycopg2 seems to be the most popular. I've never had any trouble with it. There's actually a pure Python interface for PostgreSQL too, called bpgsql. I wouldn't recommend it over psycopg2, but it's recently become capable enough to support Django and is useful if you can't compile C modules.