WoW Midgame Guide Mage Leveling

This is a guide to leveling as a mage. I'll feel on subjects such as: leveling methods, specs, and gear.

The class.
The mage is branch of the holy trinity of MMO-classes: warrior, priest, mage. The mage is the king of DPS (especially after 1.11) and crowdcontrol (CC) and has value as well (water/food/portals/buffs).

Leveling methods
As a mage you contain 50% more options to level, than other classes have. Either you choose, I highly suggest doing nothing but instance from 58-60 to gear up and get all your key quests done. Not responsibility, means missing out on a huge amount of XP.

The traditional ways are:

Grinding:
Not much to say on this. You kill mobs, they give XP, you lv l. If you don't have a comprehensive knowledge of where quests take you and which order is best, grinding is fast for leveling.
It can be pretty boring, but listening to music or being on Vent/TS helps a lot. Get a rhytm going and stay in it. Take break when you mana up to not go completely blind :)

The following is pretty good list of where to grind which mobs. It is however from a Horde viewpoint and you need to scroll down a bit to get to the guide :) If you read the whole bit, there are some suggestions for alternative, which work just as well..if not better.
wow leveling mage

And the following lists some nice alliance spots for grinding. Also are some suggestions on questing.
wow leveling alliancel

Questing:
If you know your way around the world, this is the greatest way to level up. This is also known as gresting to some. Decent horde guides are few and far between (there are some on this site), alliance have it a lot improved.

Horde - if you are horde, use Joana's guide. That will take you from 1-60 in 5 days /played. It's written from a hunter perspective, so my idea is staggering your progress in the guide by a lv l or two. Other than that, there are some (admittedly with hole in them) guides here in the strat section. An idea is to try and modify the subsequent Alliance guide.
wow leveling alliance guide
wow leveling vidoe are links to all the videos (thanks sQren)

Alliance - if you are Alliance, you got it made! The following guide will quickly and easily take you from 30-60. Reason it's 30, is because of the quests pre that are in and around the starter areas, so just level quickly to 30 and you are set.
wow leveling 30

AOE'ing:
This is where the mage can level differently. By using their Area of Effect spells, they can decimate scores of lower level enemies, thus gaining experience quickly.
The most comprehensive guide to AOE spots is from the official WOW forums
wow leveling forum

Doing it this way, takes some learning and it goes a lot smoother if you duo'ing, either with another AOE class or a healer. But you will level pretty quickly.

Talent Specs
For leveling I recommend Fire, then arcane or frost. For optimal leveling, you should respec at 58-60, when you start to raid. When you start to end-game raid, you should respec once again. I will also make a mage end-game guide, where I will touch upon these points.

Some people recommend ice for leveling, especially after 1.11, but I still prefer fire: damage from frost is dependent on crits and fire isn't so much. The base fireball has higher DPS than frost and with fire you have longer range.
Here is a small discussion of fire vs frost.
wow leveling fire v frost

This is the spec I suggest for leveling. This works very well when grinding, since you can DPS relatively well in melee with scorch or wand. Of course, it also works for gresting :) :
wow leveling grinding

Focus on improving your fireball up to lvl 40 (reduced cast time first, then stun. Rest is up to you), then put 7 points in arcane up to wands, then the rest in fire and finally the last points in arcane.

Method of pulling: Max range, then Pyroblast, Fireball, Fireball and then either fireblast/scorch/wand until dead (if you are lazy) or Frost Nova, get range, Fireballs until dead.

This is the spec I suggest for AOE'ing. It's based around frost and it's AOE abilities.
wow leveling aoe
Go up through through ice to improved Blizzard, then fill out arcane, then go ice until 60.

Method of AOE'ing: If the mobs are grouped, get max range, pop Ice Barrier and Blizzard them. You should be able to get 2 off. Then Frost Nova and Cone of Cold and Arcane Explosion until they die. If things get too hot, Ice Block, Frost Snap, Frost Nova, Ice Barrier, get range and repeat.

Gear
If you are grinding or gresting, you should go for +dam gear. Fireballs are on a 3.5 sec cast time, so get the full effect from the damage gear. Mana isn't really a concern since you have free drinks. Sip after every pull or every other pull, then you'll be fine.
If you are AOE'ing, you need a mix of INT and STAM if you don't have a healing buddy. You will mostly be casting instants or long channeled spells, so you will not get so much use out of damage.

When you start getting to 50+, this is a list of damage gear you should get:
wow leveling 50

And to further supplement the above list, this is from the official forums:
wow leveling warcraft