auditing DHCP

We are a fairly open university campus, and would like to implement DHCP on a more universal basis. The issue we are having trouble with is being able to identify machines and their locations in the event of a problem. Like any higher ed facility,we get students trying to go where they don’t belong, and occasionally an outsider slipping in with a handy laptop. We need to secure against the latter, and be able to trace the former. Does anyone have any experience with this? Ideas? Thanks!