Sorry about that. WG = Wintersgrasp, the BG that you can do every 2 1/2 hours.
Honor is like currency now, yes. The old marks for AV, AB, WSG, Eye of the Storm and Strand of the Ancients can now be turned in for honor which you can then use to buy gear. Rings, neck and cloaks in particular, like:
Deadly Gladiator's Band of Ascendancy - Item - World of Warcraft
Wintersgrasp has its own separate marks of honor that can be used at a vendor in the little fortress there when your faction controls the zone. Things like
Titan-forged Leather Chestguard of Salvation - Item - World of Warcraft.
There are also items that you can buy with honor but require a specific arena rating and items that can only be bought with arena points that also require a specific rating.
Just to make things more complicated, controlling Wintersgrasp opens up a raid zone called Vault of Archavon. There is a 10-man and 25-man version and the two bosses in there both also drop PvP gear as well as PvE tier items.