IDLE is itself written in Python, using Tkinter, Python’s de facto cross-platform GUI package based on Tcl/Tk. Because Python and Tcl/Tk are cross platform, so is IDLE; it works as well on Windows (95, 98, NT) as on Unix (including Linux), with minor, unavoidable differences because of inherent differences between the platforms. It also works on Macintosh (although occasionally you may experience a slight problem, because this platform gets less testing).
This section describes IDLE Version 0.5, which hasn’t been released at the time of writing. The Python 1.5.2 distribution comes with IDLE Version 0.4, which differs in a number of details, so these will be detailed where appropriate. In any case, IDLE requires Python 1.5.2 or later to run. Tcl/Tk 8.0 or later (optionally installed with Python 1.5.2) is needed.
As the version number should imply, IDLE is still a young application, and features are developing at a great rate. Check the online documentation regularly to keep up with the current feature set.