tbc frost mage

I'm no mage expert but there are basically two choices, either go 17/0/44 for improved counterspell or leave it and dump nearly all your points in the frost tree.

Imp counterspell is probably the superior choice ands the spec ressembles this :
http://calculators.iradei.eu/talents...11205010221251
With 3 points left for frost talents of your choice. I'd go 3% hit (1st tier) or winter's chill (between cold snap and ice barrier).

In arena the class is top or 2nd tier and will perform extremely well with a rogue as a very bursty duo with great control against casters and melees alike. Warriors will cry if their healer can't dispell your roots, and even then there's your rogue's crippling to peel.
The comp will apply extreme pressure on most opponents, although when facing a rogue you wanna make sure your team gets the first sap.
Being able to eat/drink as a double dps team is also neat.

Then there is SP/Mage as another double dps route or Disco/Mage which I have never played (being a rogue) but is one of the very scary duos in TBC. Less burst, much more survivability.
Some mage or even priest players might tell you more about it ! I know it's a powerful and pleasant duo to play.

For 3v3 you've got the almighty RMP, once you master it (or justl kinda know what you're doing) it becomes one of the strongest 3v3 comp.

All in all frost mage in tbc is in a very good pvp spot... you can't go wrong !!