There are a bunch of guilds. You can read about them on the guild discussion section of this forum or look at the list on the wiki -
http://wiki.project1999.com/Guilds:Guild_List (some guilds might not have updated this in a while).
I personally would encourage you to get into the game, group with other low level players and make friends before jumping into a guild. Don't be shy in game /tell others around your level and try to form groups. I think guild choices will evolve more naturally later on as you level and make friends. I understand many prefer to get into a guild right away though, so up to you.
Take advantage of the wiki. EQ doesn't offer much in the way of in game guidance, so I think you will find class guides, newbie guides, zone maps etc on the wiki extremely valuable as a player fairly new to EQ.