fetchmail

I wish to use fetchmail to fetch email from my pop3 host, and then filter it through spam-assassin. This I have working; the problem I have is I'm not sure fetchmail runs every x minutes and I seem to recall in the past having set it up to do this but for the life of me I can't remember how.

Basically, what I want to know is how to make fetchmail fetch my email every 2 minutes?

Mandrake 9.0