Good tips from Edy, Ill add another one - use Mage Armor against DKs instead of Frost armor, it will halve the duration of their magic effects such as Icy Touch and Strangulate. Actually it helps to have a one-button macro for swapping between Frost and Mage armor as you see fit.

I have a 53/18 Fire/Frost spec for BGs and arenas. Playing a Fire Mage in BGs has to be the most action packed and fun thing to do in wow imo. I haver played it since watching Otherguy's Sorrow Hill series way back.

Im specced into Shatter for a quick Scorch->Fireblast->Hot Streak Pyro whenever Frostbite procs, but I find myself running out of mana very quickly so Im considering swapping those points into Frost Channeling instead. Would like to get the Mana Gem glyph too but I dont know what to drop out of LB/IV/Evocation.

Id say mana usage is my biggest problem at the moment in arena and BGs.

Christian - another Fire based PvP Spec ive seen around is 17/54 Arc/Fire, with Improved CS. Havent played anything like that myself since Vanilla Wow 21/30 w/POM however so I dont know what its like these days.

Flekz Fire PvP videos are great too.