Glancing at the standard Python modules is a great way to learn. They are generally high-quality and will reveal many hidden tricks within Python (this is where I learned generator expressions).

Also I like Googling for "python tricks" as there are many gems hidden just waiting to be discovered. Here are a few examples:

http://kogs-www.informatik.uni-hamburg.de/~meine/python_tric...

http://www.siafoo.net/article/52

http://stackoverflow.com/questions/101268/hidden-features-of...