Mic switch forward activates VHF AM.
Down activates UHF
Aft activates FM
Up does nothing in game. I'd hazard a guess it does something for the secure radio.
wouldn't it be fantastic if that turned out to be a rude word. (I put it into google and apparently it's Irish and mean Black Happy Birth, aah, fun times. :D)
Recommend you check out the squadron listing on the wiki (gimme a sec), lists everything from casual to hardcore. Alternatively just jump on any servers in the mp list.