Whelp, societies as they existed at the beginning of the game, or even a year after release, no longer exist. The core piece, to provide a vendor, broker and quest giver still exist, but they no longer have "levels" and hence, cannot be "improved", nor are there "wholesalers" or "professional" societies anymore.

Q: So, what is a society?
A: A society is a group of NPCs running any particular tradeskill instance. Certain services are provided by or near these groups to the tradeskillers. You'll find the services of a vendor for tradeskill supplies and books, a broker, and a task giver.

Q: So where are these societies?
A: A list of the tradeskill instances are here. Check out the way points - they should help you find them in game!

Q: So what's up with the tasks?
A: They're going through changes. Hopefully I'll remember to update this when we find out! Be sure to check out the rest of the site and boards for more up-to-date information. (*cough*)Search(*cough*)

Q: I can't join the wholesaler/professional society in my hometown, what do I do? (Or I've forgotten which one I've joined ... or I betrayed and forgot to leave my old society ...)
A: Chances are, you're a member of another such society somewhere. While there used to be a societies option under the EQII button, making it easier to see/leave your societies, this button was removed with LU19. Use the following command (case-sensitive) to call up the societies window, to view your memberships, and to leave them as needed: /show_window MainHUD.Society

Q: Anything else I should know about societies?
A: This article on the main site has additional useful information.