We'd expect our 32 GB iPhone 4 to fulfill its promise and give us, well, 32 GB. Unfortunately it has an actual capacity of 29.06 GB.
In terms of OS, the iPhone 4 comes preinstalled with the newly released iOS 4, build 8A293.
The iPhone 4 is Model A1332. Interestingly, that's a lower number than the A1337 iPad 3G.