As of Python 2.3a2 the only sure way of getting MacPython-OSX on your machine is getting a source distribution and building what is called a "framework Python". The details are in the file Mac/OSX/README.
As binary installers become available the details will be posted to http://www.cwi.nl/~jack/macpython.html.
What you get after installing is a number of things:
To uninstall MacPython you can simply remove these three things.
PythonIDE contains an Apple Help Viewer book called "MacPython Help" which you can access through its help menu. If you are completely new to Python you should start reading the IDE introduction in that document.
If you are familiar with Python on other Unix platforms you should read the section on running Python scripts from the Unix shell.