There are a couple of creams on the market that are supposed to diminish scars, including stretchmarks. The one that comes to mind is called Maderma. This is not a "beauty" product, but rather a pharmaceutical developed for people who have been scarred through surgery, accidents, etc.

I don't know how effective it is, but I will probably being trying it myself. I know they will never completely go away, but if this can help fade them a little, I'd be grateful enough for that.