Pyrepl is a neat replacement for python readline module.

Features: 
 - sane multi-line editing 
 - history, with incremental search 
 - completion, including displaying of available options 
 - a fairly large subset of the readline emacs-mode key bindings
   (adding more is mostly just a matter of typing) 
 - Deliberately liberal, Python-style license 
 - no global variables, so you can run two independent readers
   without having their histories interfering. 

WWW: http://starship.python.net/crew/mwh/hacks/pyrepl.html