A dedicated game server (one of the server setup options, the one titled "dedicated" with options for none, Internet or LAN) shows up automatically on those lists, though you might need to fiddle with the Show Empty filter and hit "Get New List".
A non-dedicated server (where the computer hosting also enters the game) doesn't show up here, it's to do with the way the MP server was written, deliberatly to reduce the load on the master server lists at Raven. You can still join it, but you will have to connect directly to it's IP Address. Alternatively you can start a dedicated server first, then run JK2 again and join the new dedicated server (you'll find it under Local games if you do that).
Me, I'm glad I have two computers :>
PS: No, you can't have two lightsabers in the game. Much to many peoples distress. I suspect a mod is in the works though.