http://www.cisco.com/warp/public/477/SNMP/12.html will tell you how to configure the SNMP Community Strings on the Cat4006 switch. Refer to the section 'How To Configure SNMP Community Strings on a Catalyst Switch' in the above URL.
To set the location, use 'set system location[location_string]' command, where location_string = (Optional) Variable text string that indicates where the system is located.
To set the contact information use the command 'set system contact [contact_string]', where contact_string = (Optional) Variable text string that contains the name of the person to contact for system administration. If no contact string is specified, the system contact string is cleared.
As always, as good practice, refer to the Command Reference at:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4000/rel7_2/cmd_ref/cr_toc.htm#xtocid14 for details on the above commands as well as other relevant info. Hope this helps.
