If you were looking for a way to progress further, you could consider some online challenges. And as with most games, there is an online spoiler, which will help if stuck on the first few, but you won’t learn as much.
There are also some good books available, but I haven’t read any so can’t recommend a good one.
Thanks go to Apple for including python on Mac OS X, which means you can start from the Terminal:
gmwils@mayumi % python Python 2.3.5 (#1, Mar 20 2005, 20:38:20) >>> 2**38 274877906944L
My own route to learning python was that I was sick of perl, didn’t want to use Visual Basic and needed to do some COM programming on Win32. Having previously spent way too long coding in Haskell, I’ve jumped into python with somewhat of a content sigh. I’m actually happy coding again :)
Now that I can use Python for Windows programming I’m going to try to dodge Objective C on my way to Cocoa programming.