Trading that in it's possible you may get enough for a 40gb PS3, phone a couple of retailers tomorrow and they will give you a price over the phone. You may be better off selling it on eBay though as you won't necessarily get the best price from a retailer. You'll likely get more money on eBay, it depends if you want the hassle.
it is surprising how much they actually for on ebay, i'd go that route.