Quick version since Im getting up early tomorrow.
Gear for dps, hit expertise caps are nice, and as much str and crit you can muster. I would not recommend gearing for any defensive stats or gemming/enchanting for resilience. With normal pvp gear and the base line talents from prot, you wont need them. Play in battle stance only jumping to defensive or berserking when you need to use an ability exclusive to those stances.
Your goal as prot is to help control the fight....not kill stuff. In other words it is more important to interupt casts, lock down players, and protect your team mates. Unless you are primarily doing 2s arena. If that is the case reroll arms or fury because the lack of prot damage will really slow you down in the 2s bracket. Use your vigilance, properly applied your vengence should be climbing the entire fight. WHen you get up to 20k+ attack power those shield slam crits get to be a lot of fun.
A couple of useful macros, which you should be able to lookup or figure out how to write them:
macro hamstring to charge/intercept
any ability that you need to switch stances for needs a macro ie. shield wall, recklessness, disarm, taunt (for pets), and intervene.
This is just stuff off the top of my head so im sure ive forgotten a lot of useful information. If you come up with some more specific questions ask away and I will do my best to answer them.