Using Judgement is typically referred to as "Judging" a target. Judging a Seal a Paladin has cast on himself can result in a myriad of abilities, from damage to utility debuffs. If the Judgement is a debuff, the duration of it can be refreshed each time the Judging Paladin lands a melee hit.
Talents directly improving Judgement
The Retribution tier 1 talent [Benediction] reduces the cost of Judgement and Seals by 3/6/9/12/15%.
You can decrease the cooldown by 2 seconds of Judgement with [Improved Judgement] (2 ranks, 1 second per rank) in the Retribution Tree.
[Sanctified Judgement] (3 ranks) gives a 33/66/100% chance of receiving 50% of the mana back of the judged seal.
The Retribution tier 8 talent [Fanaticism] increases the critical strike chance of any Judgement that is capable of critical hits by 3/6/9/12/15%; this would include Righteousness, Command, Vengeance(?) and Blood.
Judgement deals Holy damage to enemy, harming the Paladin for 33% of damage dealt.
melee / melee
The Tier 2 Paladin armor set is called Judgment Armor and includes an 8-piece set bonus that inflicts 60-66 additional Holy damage to the target a Paladin is Judging.
The set also offers a distinct and fitting look for Paladins and many Paladin-centric armor pieces in the Burning Crusade expansion have used variations of the Judgement set, normally a different color theme.