What you want to do is keep an eye at the Apple website for their refurb'ed iPhones.
They're refurb'ed by Apple and no one can do it better than Apple - you won't tell from new and they carry the same warranty.
I just checked and they're out now but do keep an eye for them..
PS - the new iPhone is supposedly about to be released soon so if you hang in there you can either buy the latest and greatest (it'll cost ya') or get a deeper discount on the current ones...