New England Journal of Medicine just put out a big review of trans fat I believe in 2006. Even when it says on the label 0g trans fat it can still contain some due to legislation in the USA. Look for no "partially hydrogenated oils" in the ingredient list.
Hydrogenating oils not only gives them a different texture (as in PB) it also extends the shelf life of the product. So just storing peanuts will over time cause the fat/oil to oxidize and go rancid. If you do store peanuts you will have to rotate them relatively frequently.
I agree with your sentiment though...with a history of heart disease in my family the last thing I need is some dietary trans fat to exacerbate my genetic potential for a heart attack. No more skippy for me.
Cheers,
Nemo