Blackwing Lair

Blackwing Lair is located in BRM. If you've been to UBRS, you may have noticed a corridor with a (green) raid portal down one of the corridors. Like Molten Core, there is an easier way to enter once you've been attuned. The attunement quest is listed here. Basically, you have to kill the Quartermaster outside BRS and loot a note off of him, then kill the General in UBRS and interact with the orb behind him. Once you have done that, the orb behind the Quartermaster will take you to BWL if you're in a raid group.