Is there a way to find out who joined the channel/server without having to switch from the game to teamspeak? Some voice telling you who joined, a pop up message like in MSN messenger or something like that?
One good idea is to; ask who joined. Other than that nope, if you own the server make a rule in the FFA to announce themselves when they join.
1) Get a G15 that shows you
2) Get a Second Monitor that shows you
3) Ask who just joined
2) Get a Second Monitor that shows you
3) Ask who just joined