Stitcher, the personalized streaming radio service, is releasing its native iPhone application in a limited private beta. The first 100 TechCrunch readers to submit their email addresses here will be eligible to participate. Note that you’ll have to submit your iPhone’s serial number, which is required by Apple’s Ad Hoc beta program (as is the 100 user limit).

Stitcher can best be described as Pandora for everything but music, allowing users to compile a playlist of audio feeds from hundreds of sources, including news sites and radio stations. The site also employs a small team to read popular blogs and websites aloud so you can listen to them on the go.

When I first covered Stitcher in May, I wrote that the site’s mobile service had a lot of potential, but that its iPhone web app was slow and clunky (which was more an issue with Mobile Safari than Stitcher).

The demo video below shows that Stitcher’s native app has resolved these issues – there’s no longer any lag when switching stations, and the interface is much cleaner and more intuitive. Once it launches on the App Store, Stitcher will see no shortage of competition from other audio streaming apps including Pandora (one of the most popular apps in the store), AOL Radio, and a number of others.

You can see a demo of the app below. Note that Stitcher is a work in progress, and that the team is still making improvements as it builds up to public release: