Where can i find the user's crons?

I see in the toplist of teh resources this:

/usr/bin/wget -O/dev/null -q http://autohits.dk/autohits.asp?UserID1099463217

I think somebody is generating hits from our server (I don't think they have hacked the server just for this).

* AND *

How can i search the cron files for this line?