Mage in WOW is one of the best and only AOE classes except a Warlock. A frost mage have more survivability over the fire spec. This farming Sunfery Signets with Mage will help you average approximately 100 sunfury signets as well as possibly 5 arcane tomes. This itself should yield over 100 World of Warcraft gold. More than likely you will also be receiving lots of rare items and recipes here as well. This farming method is not only ideal to farming for WOW gold but also for WOW leveling your characters.
First of all, your Mage should be with 400 at least and somewhere close to 700 bonus frost damage that will do fine. Also your Mage should have these abilities in their talent tree.
Requirement: water elemental, ice barrier, ice floes, improved blizzard, and cold snap. There are also other spells that I highly suggest getting such as permafrost, ice shards, piercing ice, icy veins, shatter, improved cone of cold, arctic winds, shattered barrier, fingers of frost, improved water elemental and deep freeze.
First place to go is Netherstorm in Outland which is one of the highest level zones in World of Warcraft as of the Burning Crusade expansion. With skill and practice, you can start farming with your mage at about level 67 to 68. Ideally 68 because of the "to hit code" that you will face at lower levels. This is a great way to level yourself, gather World of Warcraft gold and build your faction with the Scryers. Once you arrive at the neutral town of Area 52, make your way a bit south and west until you reach Mana Forge B'naar.
When you get there, find 3-5 camps of sunfury mobs to kill. At the very beginning, you should try small groups of maybe 3-5 for practice until you are more comfortable with the surrounding and the method you should use. Then get to your mount, Grab a small group of 5 with your mount and pull them onto a safe isolated spot where you can kill them without interruption of your casting. Once you have them at your sweet spot, frost nova them down, blink away, bring out your pet if you need and start casting blizzard. Should they get close enough to hit you and your frost nova is not back up, use your pets. Freeze them again, rinse and repeat with blizzard, cone of cold or arcane explosion.
Once you get enough practice, you are able to handle these mobs like a professional. You can kill a group of 20 easily. Even though, this is a little boring, it is still one of the fastest and most commonly used methods for making World of Warcraft gold. Keep in mind this WoW gold farming technique requires lots of repairs on your gears as you will be getting hit quite often.