I still like to use DrPython, but you need to instal the wxPython GUI toolkit first (something you should have anyway). DrPython has some neat downloadable plugins like 'codehelp' and 'run from buffer'.
Another rather robust IDE I have used is UliPad, download from: http://code.google.com/p/ulipad/
For instance ulipad.3.9.exe is a full Windows installer and brings along Python and wxPython for Windows computers that don't have Python installed. UliPad handles a large number of computer languages, not just Python.
thanks at the moment i have programmers notepad but i really want something that will allow you to test the code and that is also cross platform, i am looking at ulipad but if i dont find that usefull do you know any free ones that i could use?