If you want to give access to the nodes on the mesh using any computer, tablet, or smart phone that has WiFi you can do it by connecting an airGateway to your Power Over Ethernet (POE) adapter.
Before the airGateway was available you could build a "double stack" as shown above. The top WRT54G is running the Linksys firmware so it is acting like a normal WiFi router. The bottom WRT54G is running the Broadband-Hamnet.org or AREDN.org firmware and is a Mesh node. The two routers are connected by a short cat5e cable that goes from the Internet port on the top WRT54G (Normal router) and goes to one of the Services (LAN) ports on the bottom WRT54G (Mesh Node). Now when you browse for available access points you will see the ssid of the top router, and when you connect to localnode:8080 you will see the Node Status page for the bottom WRT54G.
That's cool but using two WRT54G's takes up a lot of room in my Go-Kit so now I just connect one of the airGateway devices to the POE that powers one of my Mesh Nodes and it does the same thing.
All you need to do is set the ssid (and password if you want) on the WIRELESS tab of the airGateway and then go to the NETWORK tab and change the Network Mode to Bridge. See sample NETWORK tab below.