This tutorial will teach the basics of wxPython by example and experimentation.
The tutorials are meant to be run, read, modified and completed. For best
results, change anything and everything you are curious about. Also 

learnWXPython is written by:
Josh Orndorff
admin@joshorndorff.com
www.joshorndorff.com

Additional resources are available around the web:
http://wiki.wxpython.org
The official wxPython wiki. It has been down for troubleshooting for a while.
I'm beginning to wonder if it will ever come back up.

http://zetcode.com/wxpython/
Another 3rd party tutorial that I've referenced in writing my own tutorial. It
is written in the more traditional style of providing examples and explaining
how they work.

http://wxpython.org/docs/api/
The official wxPython API documentation. It is relatively complete.

http://docs.wxwidgets.org/
The official WXWidgets documentation. wxWidgets is the c++ library on which
wxPython is based. It is developed upstream of wxPython, and this documentation
technically doesn't have anything to do with wxPython. However, wxPython is
written to be similar in structure to wxWidgets, and the wxWidgets documentation
is more complete and up-to-date than that of wxPython so it is of use.