Reuse and Recycle Program." Right now, a pristine 16GB iPhone 4S will net you $285 at Apple's site.
It's not the highest amount by any means. For example, Gazelle will give you $297 for an AT&T version of the same model (note that Apple doesn't differentiate by carrier, but most third-party sites do). What's interesting is that we would have expected Gazelle's offer price to have gone down since our earlier story about a week and a half ago, but it has not.
Notably, Gazelle will allow you to lock-in the offer and keep your current device, until after the iPhone 5 launches in retail.
eBay's Instant Sale program, will give you slightly more for the same 16GB AT&T iPhone 4S, or $300.
Apple's current high offer for a device is $345, for a 64GB iPhone 4S.
As with all of these services, the device will be examined when Apple receives it, to determine the true value. You will receive the value in the form of an Apple gift card, which will prevent you from spending it on something either than the iPhone 5 - so if you have trouble with that sort of thing, it could be a plus making up for the slightly lower offer.