I dont have any tutorials but ... Upload your script to includes/cron folder and setup Schduled Tasks from adminCP.
LOL Really??? Is that how you do it??? Slap my mouth and call me a horndog.. I would have never thought of doing that.. Actually, I have done that already but I'm not sure I have my job set right.
On a related but side question.. is there anything in the vbulletin cron job scheduler that would cause it to execute a script multiple times during a scheduled run? How would one go about debugging something like this?