I can only direct you here: http://www.smogon.com/forums/showthread.php?t=83057 (it's a little complicated to explain). It basically involves you changing your date and time to what the RNG Reporter (the program you use) tells you, then hit the time correctly. That's basic. There's other complicated stuff you have to contend with.
I think Team Preview ruined it for me. It seems a minor problem, but I just preferred Gen IV where you didn't see each other's team beforehand. Then there's all the weather craze in OU. I'd probably get into RU or NU if I did decide to give it another go though. A lot of my favourite pokemon are in the lower tiers :p
I don't know what it is exactly, but it stands for Random Number Generator, and it's what the games uses to determine things like a pokemon's IVs, ability, shininess etc. It's not hacking, it's just what's programmed onto the game carts, and so people can abuse it to get perfect IV pokemon/anything they want really (within the confines of legitimate game data of course, hacks are still hacks :p)
I haven't really battled much in BW, if at all. I did some at the start, but I just lost interest in it. I battled much more back when Gen IV was around :p
Same really! Although I originally joined up for the trading section, because there's a lot of RNG'd mons on here. But since I can RNG most things myself these days, I just tend to lurk the battling sections now ^_^ Hopefully one day I'll get back into battling :3