In general, you get to your Order Halls via Dalaran (except for mages, death knights, druids and monk who have personal teleports).
How to get to Demon Hunter¡äs Order Halls
As Demon Hunter, you need to head to Krasus¡ä Landing. There is an opening on the other side were you can jump out. Aim for the small floating island and use the ability Fel Rush two times and then Glide all the way to the island. On the small Island there is a portal that takes you to you Order Halls.
How to get to Death Knight¡äs Order Halls
As a Death Knight, you will have a teleport to your Class Order Halls.
How to get to Druid¡äs Order Halls
Druids will have a teleport spell to your Class order halls.
How to get to Hunter¡äs Order Halls
Hunters take the flight path (from Dalaran) to Trueshot Lodge in Highmountain. NEW: There is a big eagle to the left side of the flightpath platform in Dalaran. Take the flightpath and talk to the tauren Talua for a ride.
How to get to Mage¡äs Order Halls
Mages will get a teleport spell while doing the Artifact Starting quest.
How to get to Monk¡äs Order Halls
As a Monk, you already have a teleport to your Class Order Halls.
How to get to Paladin¡äs Order Halls
The paladin class order halls portal is located at Sunreaver¡äs Sanctuary (Horde) and The Silver Enclave (Alliance).
How to get to Priest¡äs Order Halls
The priest class order halls portal is located at Sunreaver¡äs Sanctuary (Horde) and The Silver Enclave (Alliance).
How to get to Rogue¡äs Order Halls
Enter the Store Glorious Goods in Dalaran. Enter the Hidden Corridor to the left to enter the Class Order Halls for Rogues.
How to get to Shaman¡äs Order Halls
The Shamans have a portal located in Kraus¡ä Landing (the big platform were flight path is located)
How to get to Warlock¡äs Order Halls
The Warlock class order halls portal is located in the sewers of Dalaran, directly when you come down the stairs.
How to get to Warrior¡äs Order Halls
Travel to Kraus¡ä Landing (the big platform were flight path is located) in Dalaran. On the right side you will see Val¡äkyr of Oden and a light next to her. Step into the light and an extra button will appear (Skyjump to Halls of Valor), click it and you will get tossed up to Warriors class order halls.