You need the Cold Weather flying skill. It is available at the Dalaran Flight Trainer for 1000g and you must be level 77.
There is also a Tome of Cold Weather Flying available at that same trainer, but you need to be an 80 to buy it. The Tome gives you Cold Weather Flying for your alts that are 68. It is Bind to Account (BoA) but is consumed when one alt learns it. You have to buy one for each alt ya want to fly.
Hunter's do not get a class specific mount. They use the same mounts as everyone else. The only classes that have their own mounts are: Warlocks, Paladins, and Death Knights. Druids get a spell to shape-shift them into a bird that can fly in outland and northrend. This spell typically serves as their mount.
In Wrath of the Lich King, the mount levels were changed big time. Level 20 will allow you to get your first mount and at level 40 you can get the epic land mount. Level 60 will allow you to fly in outlands. Level 77 will alow you to fly in northrend once you have purchased the cold weather flying skill (level 68 if you have an 80 and can buy the tome of cold weather flight). Epic Flying is still level 70 and costs 5000 gold.
No only wrath to go to northrend but burning crusade to go to outlands among other restricitions
From what has been said on most of the forums that deal with the coming expansion, once you hit 60 and purchase the regular flying mount training, you will be able to fly in Eastern Kingdoms and Kalimdor. Note, this does NOT affect Northrend Flight...meaning you will still need to purchase the Cold Weather Flying to fly in Northrend.
at 30 you get your mount, at 60 you get your epic mount, at 70 you can get a flying mount(that only works in outland) and an epic one if you have over 9000 gold, at 80 you get a more special flying mount that can fly in Northrend.
WG means Wintergrasp, a zone in Northrend where PVP happens a lot, and a battleground that happens every 2 hours.
You must reach Level 60 in order to fly a mount. However, if you are a Druid, you learn flight form at Level 58. At Level 60 you will get an automatic quest instructing you on where to go to learn how to fly.
Either buy it at auction for 15000g (varies server to server) or make it with plans gotten from being exalted with a Northrend faction (engineering).
If you are on your first character, level 77 and you have to pay 1000g. If you are on an alt character, and have an 80, you can learn to fly as low as 68 with the tome of cold weather flight.
60
It does drop, but it just takes a while. Also, you can only fish up the turtle mount from fishing pools in Northrend, so make sure to fish there or your chance will be zero.
The Sea Turtle mount can be fished up randomly from any fishing pool in Northrend. The chances are very small however, so expect it to be a surprise, or the result of days of fishing.