my prediction:
cortex A9 or Apple A5 dual-core 1.2ghz
1gb of ram
dual SGX543 gpu
thinner,
lighter prolly like 1lb-1.25 lbs
front facing camera slightly higher res than ipod touch, and photobooth app
back facing camera 1MP
Gyrometer
Same resolution
launch with ios 4.3, ios 5 will not be previewed.
flat back, tapered edges
atleast one new port ie. sd, usb, lightpeak,
redesigned speaker
anti-reflective coating on the screen.
same battery life
16gb wifi:$499 32gb wifi:$599 64gb wifi:$699
3G version available on at&t and verizon(it will have dual-mode cdma/gsm)
16gb+3G: $599 32gb+3G:$699 64gb+3G:$799
also you can now get a data plan contract with each carrier, which will result in a subsidized price in the 3G version.
Edit: I believe this is exactly correct. I am willing to bet on it. anybody want to challenge me. Or question any of the above items