Dive Into Python is a fantastic book for experienced programmers wanting to learn how to use Python. It's readable online, or you can buy a printed copy. It covers things such as differences between Python and other languages, how to build applications, and neat little tricks to use while working with Python. It also has a unique approach to learning, in that it provides a full script then works through it, rather than providing twenty pages of syntax with an undocumented example at the end.