In order to assist with population balancing, Blizzard is currently offering free character transfers from eight source realms to four destination servers. Here's some details on the destination realms:

"Auchindoun is an Eastern time zone realm in the Retaliation battlegroup, Anetheron is an Eastern time zone realm in the Stormstrike battlegroup, Agamaggan is a Central time zone realm in the Shadowburn battlegroup, and Farstriders is a Central time zone realm in the Emberstone battlegroup."

The free transfer window is scheduled to last until Jan. 28 at 2 p.m. PST, but they could be disabled early if the goals are met. Check out the full server list below to see if any of your characters are eligible for a free move.

Source A (PvP)
Arthas
Emerald Dream (RP-PvP)
Illidan (Horde Only)
Kel’thuzad
Mal'Ganis (Horde Only)
Tichondrious
Warsong (Horde Only)

Destination A (PvP)
Agamaggan
Anetheron
Auchindoun

Source B (RP)
Moon Guard

Destination B (RP)
Farstriders