Glcu is a project mainly written in Python, it's free.
A fork of Gentoo Linux Cron Update <http://www.panhorst.com/glcu/>
This software comes with absolute no warranty !! If it burns down your house, steals your wife or destroys your harddisk - don't blame me!
glcu is released under the GPLv2
Because I'm too lazy too write everything twice, this README File just points you too the glcu website:
http://glcu.sourceforge.net/
There is all the information you need!
...and if it's not eMail me:
glcu [at] 42nd (dot) de