Hello! I play a paladin, and I'd like to tell you how I leveled to 70. I played ret until ~35 and then I respecced protection. AoE grinding allows you to fight multiple mobs while healing yourself and dealing area of effect damage.
The main talents you will use:
Righteous Fury
Holy Shield
Blessing of Salvation
Consecration
Seal of Light
Blessing of Light
The base idea of Aoe grinding is to minimize damage taken while maximizing damage to multiple targets. The more damage you take, the more damage you deal.
A good tanking/grinding build is here:
Talent Calculator - World of Warcraft
A more PvP oriented build idea is here:
Talent Calculator - World of Warcraft
Other tips:
Keep ret aura on all the time, use holy shield before consecration, don't spam consecration since it costs a lot of mana. Single target dps is low but the build will shine when you have more mobs hitting you. I have soloed 12 mobs at once, reckoning will always proc, and you can heal yourself to full with a couple procs.
Some of my 70 tanking gear:
Heroic Judicator's Chestguard
Lightbringer Handguards
Lightbringer Waistguard
The Unbreakable Will
Sword Breaker's Bulwark with Felsteel Shield Spike
Helm of Uther's Resolve
Judicator's Legguards
Spaulders of the Thalassian Defender
Lightbringer Stompers
I'm working on a movie tonight to show you guys some of what you're in for if you spec prot.