Over the past few days, I rebooted my iPhone3G several times so that it the cache would be fresh for updates, and I know what the speed of OS 2.2.1 was like. Now, after updating to OS 3.0, my iPhone3G is now noticeably faster, both the main OS and in all of the Apps. Although I'm sure the 3G-S is even faster, this software update did make the standard 3G OS faster. The 3G network data speed and Safari appear to be unchanged though.