virtual ip, what is the right way?

In suse linux 9.1 I've two network card, the first is eth0 (192.168.0.100) and the second is the eth1 (192.168.1.100). I desire to add a new card and mantain the previous two, as eth1:1 and 192.168.2.100 address. If I write ifconfig eth1:1 192.168.2.100 netmask 255.255.255. gw 192.168.2.100 it add a new nic, but what is the right way? this or add via YaST module (as a virtual ip address from the configuration panel)? finally I desire to turn on or turn off manually the nic number 3 (eth1:1) -- kalos