Windows Users
Go to the Python download page http://www.python.org/download/ and download Python 2.6.2 Windows installer.Run the installer.
This should install Python 2.6 and IDLE.Mac Users
Python 2.5 will already be installed and the installation includes the IDLE libraries. To make IDLE a bit more user-friendly look athttp://challenge.ncss.edu.au/gsg-osx/
or
http://wiki.python.org/moin/MacPython/Leopard
Linux Users
Again, Python should already be installed and includes the IDLE libraries.To make life easier use the packet manager for your Linux to get IDLE.
It will add the application to your menus and you can make a desktop icon in order to make running it easy.