When I bought my Wet Oakle's the guy at the shop told me to use 303 protectant. I think it's made by Armour All. I just bought a bottle to do my seat covers yesterday. Don't have the stuff with me right now but if you need anymore info, I can get the bottle.
If you do use the 303 protectant, spray it on and wipe the seat covers with it. They'll be wet and feel greasy for a day or so till it completley dries. After you've used it, most stains or dirt will wipe right off with a little spray of the stuff.