The report, from BGR, states that Apple will go to an aluminum back plate, replacing the glass back of the iPhone 4 and 4S.
Apple is also planning to use a plastic or rubber, similar to that used in the iPhone 4 and 4S bumper "cases" in the device, likely as a bezel which will the front edge of the iPhone 5, which will both cover a redesigned antenna system that surrounds the new iPhone as well as joining the glass iPhone 5 face to the aforementioned aluminum back.
It sounds significantly different than the iPhone 5 that Apple struggled, but failed to launch this year. Still, there's no doubt: Apple isn't going to go two and a half years without a complete redesign of the iPhone.
Ah yes, that's another tidbit from the report. Apple will launch the iPhone 5, in the fall, around the same timeframe as the iPhone 4S. That also makes a lot of (common) sense; it could cause a lot of enmity among customers if they had just upgraded to the most-the-same iPhone 4S and a totally different (and LTE sporting?) iPhone 5 shows up.
A later release also makes sense because of LTE. Second generation LTE chipsets are expected in Q2 of 2012, and waiting until the fall would give Apple time to incorporate those.
So, iPhone 4S owners, will you be going for an early (meaning full price) upgrade again in 2012?