Enable a SNMP server under IOS

Go into enable mode, then configure mode: 

GFlop$ enable
GFlop# conf t

Create an access list to restrict snmp usage: 

GFlop(config)# access-list 1 permit 192.168.1.4

Enable the snmp server 

GFlop(config)# snmp-server location Foo Bar
GFlop(config)# snmp-server contact Foo@Bar.net
GFlop(config)# snmp-server community public ro 1

(Note: You could remplace public with the community you wants, ro with rw for using snmp with write access, and 1 with the right access list you've created.)

Sample Config

access-list 1 permit 192.168.1.4
!
snmp-server community ilovecisco RO 1
snmp-server location Garage ed
!