We're still Mystery Months away from getting to play Bioware's Star Wars MMO The Old Republic, but clearly they expect their players to be organised. No hanging around the newbie areas yelling "PLZ HELP WERE IS RANCOR TUSK NEED 1 MORE LOL" on your todd - you can get on with pre-registering your guild, or joining another, right away. Step to it, magic soldier.
The plan is you setup your Guild - complete with faction, name and server type - then have it hosted on the SWTOR directory so others can join. Alternatively, search for the kind of thing that appeals, such as PVE Empire or RP Republic or this and that and whatnot, and then go beg a group that fits those criteria to let you in.
In a second phase to follow, accepted guilds can pal up to form alliances, or alternatively mark certain groups as adversaries. This sounds especially appealing - who shall RPS declare war on? Oh, choices, choices, jaunty choices... This means you're likely to end up on the same server as your friends and frenemies, which sounds an awful lot more fun than the usual deal when an MMO launches:
"Where are you? Let's team up!"
"Yeah! I'm on Bumblebee Earlobes."
"Oh, piss, I'm on Duck Anus. "
"You better reroll then."
"No, you reroll."
None of that, then. Though they can't 100% guarantee this yet - unsurprising, as I suspect some of the larger fan and gaming sites will end orchestrating impossibly vast buddy-ups.
Then it's on to phase 3: deployment. For that to happen, you'll need to meet these criteria:
1) At the beginning of Phase 3, the guild leader must log in to the website and verify that their guild remains active and wants to be imported
2) The guild has at least four members who have pre-ordered the game by the time we initiate the import.
So long as you've not chummed up with a bunch of goddamned flakes (so don't invite Quintin to your guild), you should then be imported and ready to get your Sith on. Sounds good - does that mean the game is approaching the vaunted status of "coming soon?"
Much more nitty-gritty about guilds and the preformation thereof can be found in this extensive FAQ.