This is assuming you're using VLAN 1 as your management VLAN.
Switch#config t
Switch(config)#interface vlan 1
Switch(config-int)#ip address 192.168.1.100 255.255.255.0
Switch(config-int)#no shutdown
Switch(config-int)#end
Switch#
What you need to do is set the IP address on your management VLAN interface.
HTH