Getif

Getif is a free multi-functional Windows GUI based Network Tool written by Philippe Simonet. It is amongst other things, an excellent SNMP tool that allows you to collect and graph information from SNMP devices.

These devices include (but are by no means limited to) Windows 2000 (using the SNMP4NT or SNMP4W2K or SNMP-Informant extension agents, of course!), and other OS's as well as devices manufactured by most major network companies (i.e. Cisco, 3COM, Dlink, Nokia, etc., etc.).