Blizzard is aiming to allow Bind on Account (BoA) items to transfer between factions in patch 3.3. This means your characters on the opposite faction, on the same account, can receive BoA items either through the mail or some other mechanism.
Huge news for those leveling alts, and a nice feature for those that have high level characters on both factions with BoA gear. My level 80 Horde hunter will gladly send some BoA items to the last of my Alliance toons waiting to be leveled up.
We need to note, and read this very carefully, this change is only hopefully going to make it into patch 3.3. If it's not, do not go cry to Zarhym or Ghostcrawler or your mom that the change didn't make it in -- they are not promising, only letting us know that it's something they'd like to have for us in this upcoming content patch.
Patch 3.3 is the last major patch of Wrath of the Lich King. With the new Icecrown Citadel 5-man dungeons and 10/25-man raid arriving soon, patch 3.3 will deal the final blow to the Arthas. WoW.com's Guide to Patch 3.3 will keep you updated with all the latest patch news.