The Sunwell Plateau is a raid instance located on the Isle of Quel'Danas north of Silvermoon City. Blizzard has planned for it to become the hardest raid instance in the game until the release of Wrath of the Lich King. The Sunwell Plateau is tuned for Tier 6-geared players and the gear that drops there will be additional Tier 6 items (boots, belt and bracers), and non-set epics as well.
The instance will be open to players right from the start, but the last 3 bosses will only become available over time. The 3 gates will open automatically over time at equal intervals on all servers. The difficulty of the instance will be with the first 3 bosses being on par with Tier 6 encounters and increasing from there.