Some World of Warcraft players have been complaining that Dalaran should not be accessible to Horde players. Lore wise, this would make sense considering that the mages of Kirin Tor have thrown in their lot with the Alliance.
Blizzard Community Manager Nethaera gave word that it's still too early for players to worry about the contents of the neutral city considering that it hasn't been finalized yet.
She then gave a few hints on what Blizzard may have in store for players when Dalaran does go live with the WoW expansion Wrath of the Lich King:
Dalaran is filled with the world's most powerful magic users. While they work together, they are also filled with many different personalities and more importantly, have a bit of a crisis on their hands by the name of Malygos.
I am going to hazard a guess that the Kirin Tor are going to be using all the available resources they can to survive the onslaught.
No matter how they decide to handle this new addition to the game, we can expect that the location will have lots of new quests and fun things to pursue for both Horde and Alliance players.