I have never used SNMP before but I found the answer after 3 hours of diging.

I only had a lab enviroment with no real switch, but it worked.

Here it is what you have to do:

Download NET-SNMP-XTRA from http://www.openxtra.co.uk/downloads/net-snmp-download.php

It is free and it has full installer package of the "net-snmp" tool.

Install it on a Windows box, and start Net-SNMP from command prompt (you will see how after the install)

On the switch:

SW(config)#interface vlan1

SW(config-if)#ip address 192.168.100.222 255.255.255.0

SW(config-if)#exit

SW(config)#snmp-server community lab rw

SW#vlan database

SW(vlan)#vlan 10 name Eng

SW(vlan)#exit

From the command prompt use the command below to find the snmp port number on the switch.

C:\Program Files\OPENXTRA\NET-SNMP\usr\bin>snmpwalk -v 2c -c lab 192.168.100.222 1.3.6.1.4.1.9.9.68.1.2.2.1.2

From the command prompt use the command below to set the vlan membership for a port (vlan 10 for port 3 in this example).

C:\Program Files\OPENXTRA\NET-SNMP\usr\bin>snmpset -v 2c -c lab 192.168.100.222 1.3.6.1.4.1.9.9.68.1.2.2.1.2.3 i 10

That's it. Please let me know how did it work out for you.