I wanted to create another network in my home for my kids and guests to use but I wanted to be able to have more control over the content that was being delivered, so I used this method:

Pre-requisites

1. A currently working modem router with an internet connection (I will refer to this as router A) hopefully this is password protected
2. A new second router (I will refer to this as router B)
3. An OpenDNS account (to have more control over the websites visited)

These are the basic steps I used on a windows running machine, without being too specific.

1. Connect a computer to router A from any LAN port
2. Press start and the press or type run
3. In the run box type: cmd and press enter
4. In the cmd window type:  ipconfig
5. mark down on a piece of paper the default gateway for the local area connection (mine was 192.168.1.1)
6. make sure the internet is working by browsing to www.google.com and doing a random search
7. disconnect router A and connect router B from any LAN port
8. Press start and the press or type run
9. In the run box type: cmd and press enter
10. In the cmd window type:  ipconfig
11. mark the address used for the default gateway (this router was  10.0.0.138)
12. open any browser (I used Firefox)
13. Type the address of the default gateway for router B (10.0.0.138) and press enter
14. put in the default username and password you received with your new router and press enter
15. On the main setup page, change the local address under the network setup to 192.168.2.1 (the point is to change the third group of numbers, the one between the second and third dot)
16. If you need more access control  use OpenDNS and set DNS 1 and 2 to 208.67.222.222 and 208.67.220.220 respectively
17. Click Save
18. Wait a minute and make sure you are able to connect to router B with the new address (192.168.2.1)
19. Disconnect router B
20. Connect a cable From the WAN (internet) port of router B to a LAN port on router A
21. Connect to router B with wireless or direct to make sure the internet works
22. Visit OpenDNS to set up any other web filtering you might want.
23. For extra security place a password on both routers and just distribute the one for router B