This is mainly for me own reference, but it is probably something that other people will find useful. If you attempt to use the rlcompleter module on the Mac you'll find that tab completion does not work correctly. Apparently this is because Apple ship a neutered version of readline.
To get completion working you have to use a different argument to readline.parse_and_bind(). The base example uses:
Change that line to:
readline.parse_and_bind ("bind ^I rl_complete")