Flavio's Technotalk shows you how to use Linux on your wireless router
There are several projects focused on building quality third-party software for wireless routers; some of the most well known and active projects are DD-WRT, OpenWRT, Tomato and Sveasoft. While the last two projects only support older wireless routers (WRT54G and family), DD-WRT and OpenWRT are constantly adding new routers to their lines and have a very active community. One caveat, Sveasoft uses a business model that requires a current subscription before you can try their latest firmware versions (and the older/stable versions tend to be quite limited), so I advice you to look to the other three projects first and resort to Sveasoft if none of them work for you.Howto: Linux on Your Wireless Router