Player guilds are a special association of players, formed within the game by the players themselves. Each guild has its own chat channel and organization.
To form a guild, you must first form a full party of eight players, none of whom can be guilded. Each person must be in the same zone. The person who is going to be the group leader must visit the Guild Registrar NPC, found in the major cities of your realm. The leader must select the Guild Registrar and type /gc form. Note that your guild's name must be unique. You cannot use a guild name that is already in use on your server. It costs one gold piece to start a guild. The money is deducted from the pocket of the group leader. Each member of the guild will receive a dialogue box asking if they accept membership in the new guild. Once all members have accepted, the guild is formed.
Once the guild is formed, the guild leader becomes Guild Master. All other members are automatically given a rank of 9 and no powers within the guild. All guild powers belong to the guild master, unless the guild master assigns powers to other members by way of rank privileges. A full listing of guild commands can be found at http://www.camelotherald.com/slashcommands.php under the "Guild Commands" section.
Guilds can form together in alliances, and will share a common Alliance chat channel. For information on forming an alliance, there is a full listing of commands at http://www.camelotherald.com/slashcommands.php.