The first link posted is good and that is the way it showld be done and is done by most people , however i know another way (i havent heard people talking about it , i think because it might be robbish but it does work for me anyway)
Unlike the normal aoe grinding it is not based on blizzard and you can still be pvp , single target shatter buld to utilize this , actually it might be better using the shatter build with couple of adjustements.
Anyway more to the point ...
The talents you need is shatter ,arctic reach, ice barier, imp Cone of cold , and other talents you want, but consentrating on frost dmg (piercing ice and the such)everything else is up to you (cold snap is always good)
All you do is , gather the mobs (no casters , snipers as always)(mounted or unmounted with ice barier on), use nova , take a few steps back (JUST A FEW it showld be far enough for them not to reach you but close enough to sue cone of cold) , use flamestrike (yes its a fire spell), then STRAIGHT AWAY use cone of cold , cone showld crit on most mobs and so showld flamestrike , then just use arcane explosion to finish them off(by the time you sue arcane they will eb so low only 2 or 3 will be needed but if no crits and out of luck might take lnoger)
I have sued that tactic as long as i can remember on my new mage (its only 42 but it works purfectly) im not a super mage ,and i have crap mana and hp for my lvl , i just stack up on +frost dmg (i got only like 170 at 42 but tis alright), my mana is around 2.9k-3k and my hp is only 900-1k i almsot never die, while aoe grinding , i developed this method cause i couldnt grasp the blizzard method and i wanted to be a good pvper (1 target or more , ey for shatter which causes crits in aoe as well ey)
This by the way can be used on the mobs your lvl and not jsut green ones that showld be sued in the blizzard aoe grinding method, and youl also be next to great pvp(for the pvpers out there)
(sorry for spelling , typos, capital letters ,punctuation , im really really tired)
EDIT: (talent trees)
20-http://www.wow-europe.com/en/info/basics/talents/mage/talents.html?0000000000000000000000000000000000000000000000230320010000000000000
30- http://www.wow-europe.com/en/info/basics/talents/mage/talents.html?0000000000000000000000000000000000000000000000235320010005000000000
40- http://www.wow-europe.com/en/info/basics/talents/mage/talents.html?0000000000000000000000000000000000000000000000235320310205013001000
50- http://www.wow-europe.com/en/info/basics/talents/mage/talents.html?0000000000000000000000000000000000000000000000535320310205013001511
60- http://www.wow-europe.com/en/info/basics/talents/mage/talents.html?2000000000000000000000004000000000000000000000535320310205013001551
66- http://www.wow-europe.com/en/info/basics/talents/mage/talents.html?2000000000000000000000005500000000000000000000535320310205013001551
70 - your choise (atleast until wrath oft he lich king expansion)
Edited, Aug 13th 2007 2:01pm by kizzahunt