Need to be atleast lvl 20, talk to the Guildmaster NPC of each capital city on each continent, Guilds can have up to 100 members, and if you reach max, you can increase the limit with your guild lvl
I hope there's a high payment for this feature.
And 100 members when the guild is just created, in other words, lvl 1? ... Nice. I have high doubts that guilds will be filled at lvl 1.
Oh and I seriously want that tempura headdress. Food-on-the-go? Count me in \o/
Edit: Wondering if anyone out there who already played know the guild requirements? Surely it isn't JUST lvl 20.