Monitor Windows Server without Agent?

I’m new to Nagios, running version 3.1.0 on Ubuntu 8.1.0. What can I expect to be able to monitor on Windows 2k3 servers without loading the agent? Will I be limited to pings only and getting notifications if the server is down or are there more things I can do? Will Nagios be able to do SNMP gets and monitor like that provided I configure the correct OID?