Yes, this is exactly the purpose of CiscoWorks Campus Manager's User Tracking component. User Tracking will find end users connected to switch ports by their MAC addresses. It will then correlate ARP table entries from managed routers to populate IP information. Finally, using a small piece of software running on Windows end hosts, UT can show the username of the user connected to the port.
A 90-day eval of CiscoWorks LAN Management Solution can be downloaded from http://www.cisco.com/go/lms/ .
