The be-all-end-all Arma2 community is
www.unitedoperations.net, however you are all strongly encouraged to never play there and pretend you never knew me because I will disavow all knowledge of you should you get banned for being retarded. But on the TS3 channel I have a room called Nikov's Mountain Hall, we also play a little Minecraft etc, and we've got enough newbies swarming in right now that you should be able to blend in.
Three simple rules.
1. Shut up during pre-mission slotting, loading screens, and briefings.
1a. Shut up when anyone tells you to, actually.
2. Deliberate teamkills, regardless of reason, results in rather long and painful bans for new players.
2a. Really retardedly stupid accidental teamkills may suffer bans as well, so be sure to shout "clear backblast" before firing that RPG.
3. Never use the in-game text or VON, even for game-related communications, with the sole exception of "my Teamspeak/ACRE crashed, give me a second." We use an AMAZING mod called ACRE that simulates full UHF/VHF radios as well as word-of-mouth communication within a little bubble around you, respecting terrain and materials between two points.
3a. Don't talk when people say to shut up. Because the enemy can hear you, they will do like I do and shoot you through a steel fence if you're chatting around in team versus team.