Western Earthshrine

The Western Earthshrine

The Western Earthshrine is a ritual circle erected by the Earthen Ring for use by the Horde. It is located in the city of Orgrimmar, on a high ridge overlooking the Valley of Wisdom, accessed by a series of bridges from the Orgrimmar Skyway. Its Alliance counterpart is the Eastern Earthshrine in Stormwind City.

The Earthshrine has portals to Tol Barad and to all of the new zones in Cataclysm. The portal to Tol Barad Peninsula is always present (although unusable until level 85) and the others are unlocked after completing the introductory quest for each Cataclysm zone.

The Mount Hyjal portal is opened by completing As Hyjal Burns, and leads to Nordrassil. There is a portal near Nordrassil Inn that leads back to Orgrimmar.
The Vashj'ir portal is opened by completing Call of Duty, and initially opens into The Immortal Coil in Kelp'thar Forest. At some point in the main Vashj'ir quest chain, likely after completing [30-35] Silver Tide Hollow (confirmation needed), the portal's destination changes, leading into Silver Tide Hollow in the Shimmering Expanse. Eventually, the portal's destination is moved to Tenebrous Cavern. There is no return portal at any of these locations.
The Deepholm portal is opened by completing Deepholm, and leads to the Temple of Earth. The Temple of Earth has a portal leading back to the Western Earthshrine.
The Uldum portal is definitely open after completing Escape From the Lost City (it may be opened earlier in the quest chain, testing is needed) and leads into Ramkahen. There is no return portal.
The Twilight Highlands portal is definitely open after completing Muddied Waters (it may be opened earlier in the quest chain, testing is needed) and leads to Dragonmaw Port. Completing Any Portal in a Storm opens up a portal back to the Western Earthshrine.
The Tol Barad Peninsula portal is always open, but can only be used after reaching level 85. It leads to Hellscream's Grasp, which has a portal back to the Western Earthshrine.