Just like Pontiac, the white iPhone 3G is no more. On Apple's recently updated website, there is a link which draws up a side by side comparison between the newly announced iPhone 3G S and the iPhone 3G regular. From here on out, while the new iPhone 3G S will be offered in both black and white, the regular iPhone 3G, which has been reduced to $99, will only be available in black.
See for yourself. Either Apple is cutting costs, or they're using this as an incentive to get people who really wanted the white iPhone to buy the more expensive 3G S instead.