It turns out we didn’t need to wait for the Dev Team to jailbreak iOS 4.1 after all: if you’ve got a jailbroken iPhone 3G or 3GS running the iOS 4.1 beta, all you need to do is download the HDR Camera Enabler through Cydia from the ModMy repository to enable high dynamic range snaps on your last-gen iPhone.
Presumably, this same tweak will also work with the Dev Team’s official iOS 4.1 jailbreak, which has yet to be released. Unfortunately, for right now, it’s 4.1 beta only, though, making it available to only a very small subset of jailbreakers. If you want to give it a shot, though, Redmondpie has a series of good tutorials on how to jailbreak the iOS 4.1 beta on the iPhone 3GS or iPhone 3G.