link Has many good accounts and instructions as to how to tame ghost wolf. So does link
I have heard of two ways to tame ghostwolf, but have used only one of them. The first, tried, tested and true, can only be used on players lvl 66 and up. I farmed Mana Tombs until I had enough of the spirit shards to buy one of the Helms with a meta gem slot at Allarian Stronghold [Pardon the spelling, its the 2nd flight path for alliance in Terokkar Forest. Ill assume there is a similar vendor in the second Horde Flight Path.]