This is easiest with a prot specced paladin. You will be needing to have a high enough skinning level to skin the yetis in Winterspring. Around 78,42 I believe.
First you need to get a mob, I can get over 10 easy (lvl 64 right now) by using the spell Concecration to keep agro and keep them following. When you are low on health you can either pop a potion, or you can put Concecration down again. Then use Seal of Light to stay alive and finish them off easily.
Now. Once you have the skins amount of skins you want, put them on the AH, around 50s lower than the lowest price of leather on there (on my server they go for around 8g, the highest I have seen is 10g a stack.) But remember not to put up to much Leather, or the price will dramaticly drop.(from people trying to sell cheaper and cheaper....)
Types of leather the Yeti drop: Mostly rugged leather, and every once and a while you will get a thick leather or a rugged hide.(sorry i posted on explorations)
Oh ya, the guys are lvl 57 58 and i think 59.