Upstart还是Cron在Ubuntu中进行无休止的python后台进程？

I have a simple little mail queue in Python that I want to run as a neverending background process. I'm on Ubuntu 10.04 and started down the cron route but have been reading some encouragement for upstart. I can't get either to work very well or at all. Any advice?I have a simple little mail queue in Python tha