Apple's iPhone OS 3.0 provides several improvements to the way your iPhone or iPod Touch handles media playback.
One of the the most useful new features is Apple's Spotlight search, which is accessible directly from the main screen. Spotlight provides a means to search all of your content: music, email, apps, everything. Search results appear after typing only a few letters, and quickly refine themselves as you complete typing.
After you've located the file in Spotlight, selecting it will launch the file within its given app. From an iPod perspective, Spotlight provides the fastest access to finding and playing a specific song, with a minimum of clicks.