Documentation for mod_python is on http://www.modpython.org/
If you can't read instructions:
$ ./configure
$ make
$ sudo make install
$ make test
If the above worked - read the tutorial in the documentation.
HELP NEEDED! I do not have access to a Windows development environment. If you get a Windows compile working, please create a pull request or drop a note on the mod_python mailing list: mod_python@modpython.org (Note: subscription required).
At least on OS X 10.8.5, the following was required in order for compile to work:
sudo ln -s /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain \
/Applications/Xcode.app/Contents/Developer/Toolchains/OSX10.8.xctoolchain