Priest

Basic Information from Blizzard regarding Priests: The Priest class is the master of healing, crowd control, and hate control. Other classes such as the Shaman, Druid, and Paladin can heal, but not as well as the Priest. The Priest can also resurrect dead players along with the Shaman and Paladin. The Warlock also has the ability to resurrect, through the use of soul stones. The Priest has some buffs that can help party members. The Priest can even take control of humanoid monsters at higher character levels.

Valid Races: Human, Night Elf, Dwarf, Undead, Troll, Draenei, Blood Elf

The TenTonHammer take on Priests

The priest is possibly the most highly requested class in WoW when groups begin to form. Overlooking the fact that priests are capable of coping with small amounts of enemies on their own, and are by themselves a force to be reckoned with, priests are viewed by most other classes as being the best (and sometimes only) way of making it through an instance in one piece.

Priests have access to the highly vaunted ability to resurrect other dead characters, which makes them invaluable when proceeding through an instance, or fighting far from a graveyard. Priests also maintain an array of supportive magic that makes them often sought out by others.

Links to information on other WoW sites

Blizzard WoW site - The official Blizzard WoW Priest information page.
Priest Articles - Article submissions from players about Priests on "The Knights who say... Ni!" site.
Priest Character guide - Starting levels and brief talent descriptions at the wowvault.ign.com site.