The coolest iPhone 3.0 update is the way scrubbing is improved in the iPod application. If you touch and hold the scrubber, you have the option of changing your scrubbing speed. It reads, "Slide your finger down to adjust the scrubbing rate."Scrubbing the traditional way is dubbed "Hi-Speed Scrubbing". It proceeds down to "Half Speed Scrubbing" and "Quarter Speed Scrubbing" when the finger is near the middle of the screen. Finally, below that is "Fine Scrubbing".
Pretty awesome. And podcasts (and I'd imagine, audiobooks) now have a 30-second step back button as well.
(The Casino Royale soundtrack rocks.)