CMU has written a decent SNMP package that includes a library, a set of UNIX command line utilities, and Tcl and Tk interfaces. Free download and more information can be found at its web page.
One of the most useful command-line utilities in this package is snmpnetstat, which sends a series of SNMP Get requests to inquire about a remote host's network status, and presents this information in a form similar to that used by netstat to display local network information. The default display shows active Internet-domain connections. Options are available to display a list of network interfaces, or to display the remote routing table. Obviously, a working network connection is required to make use of this program, a quick and easily understood SNMP management tool.