I whipped together a sample Server List browser. It allows you to query for game servers, and to add/remove game servers from the list. It's pretty basic at the moment, but should be enough for a simple ip address exchange. I'm feel like I'm rushing this out because I'm late for work... but I think I got it all in a clean package for download, if not I'll fix it tonight.
The source code for all the operations is included, so feel free to add it to your wifi enabled games, and to use my server to store hosted game ip addresses. You'll just need to change the 3 instances of "TestGame" to your own game name.