In an unprecedented move, BioWare today revealed the Guild Headquarters on the official Star Wars: The Old Republic website. The headquarters will allow players to search for and form guilds prior to the game's release--allowing them to reserve names or team up with players immediately.
If you're looking for a guild, the search is rather simple. You can search by guild name, or member name, and it will provide a list of guilds using those names--or guilds with members going by that name. However, there's an incredibly robust version as well, providing a slew of options including the ability to search based on play style, the kind of content a guild is focused on, whether they use voice chat, and more.
Creating a guild is a fairly simple process. Log in to your BioWare account--or sign up if you don't have one--and from there you can start your guild. You have to choose your allegiance (Empire or Republic), your guild's play style, the language your guild will speak, the times your guild will be active, a guild name, your contact info and a phone number.
And while you might be concerned that they want your phone number, worry not--it will only be utilized by BioWare support in the event they need to contact you--it's not going to be passed around to anyone who looks at your guild page.