Why do you want to use 2 routers? To increase your wifi range? For additional ssid's? To increase the amount of ports because of additional devices?
If you want better wifi range, use the second router as an access point, as described above. Just make sure the two routers are on different channels, atleast 3 channels apart. Ideally, you would use a wifi-extender, because routers are layer 3 devices and could increase your collision domain and impact your bandwidth (speed).
If you want additional ssid's, or another wifi network, make sure the second router is outside of the IP Range of the first router, but use the same subnet mask. Again, change the wifi channels to decrease interference.
If you are looking to add additional ports to your network, buy a switch. You can find one for $30 or so. Switches are layer 2 devices that will send packets (info) across your network faster than the router will, simply because the router sends packets to the desired device, rather than across the entire network.
Hope this helps.
Edited by Donald.CNS, 23 November 2012 - 02:07 AM.