Many people use Python on websites, but the Python is running on the server, not on the client. You can use Python to make a page dynamic (perhaps it changes everytime you view it, like this forum).
Unfortunately, geocities (and other free webspace providers) won't let you run your own custom-written programs on their servers, since it would constitute a security risk.
My suggestion, if you're willing to do a bit of learning, is actually to install your own webserver, and serve your own site from your own PC. You can install apache (a webserver) and modpython (the plugin which allows apache to run Python programs) even on a Windows machine, I believe.
If you want to show your dynamic, Python-powered website to the world, there are some subtleties -- for example, if your IP address changes often, you'd have to use a dynamic DNS service.
However, wScott, I strongly recommend that you don't start your career in Python by trying to develop web software. Instead, I suggest you start with command-line programs, then work your way up to desktop GUI programs, then move on to web applications.
- Warren