Apple on Wednesday released the iPhone 3.1 software update, as predicted. Apple CEO Steve Jobs introduced the update on stage at the Yerba Buena Center during the “Rock and Roll” event. The software includes a handful of new features and bug fixes.

With over 75,000 apps in the App Store, it can be difficult to find new applications. Apple’s extended its Genius media-recommendation algorithm to iPhone applications. It looks at the apps you already own and makes recommendations based on that information.

In addition iPhone 3.1 beefs up the iPhone’s ringtone capability, allowing you to download over 30,000 ringtones from major labels via a Ringtones section in the iPhone’s iTunes application. Ringtones will cost $1.29 apiece, and automatically show up in the iPhone’s Settings once they’ve been downloaded.

Also included in the iPhone OS 3.1 update are a number of iTunes 9-related features, such as support for Genius Mixes, automatically generated playlists of tracks based on your library; the ability to organize applications on your iPhone's Home screen in iTunes; new syncing options for music, movies, TV shows, podcasts, and photos; and iTunes U content organization.

Furthermore, iPhone 3.1 brings with it the ability to redeem iTunes gift cards, codes, and certificates in the App Store (a feature that briefly appeared in iPhone 3.0 then later disappeared) as well as a way to view available iTunes account credits in both the App Store and iTunes Store.

Video features get a couple of new additions in 3.1 with the ability to save videos from both Mail and MMS into the Camera Roll (U.S. users will have to wait for AT&T to roll out MMS functionality on September 25 in order to use the latter). You can also now save a copy of a trimmed video clip, which avoids overriding the original clip.

On the iPhone 3GS, Voice Control is now accessible via a Bluetooth headset and there's an option to use the 3GS's Home button to activate Accessibility features.

There are a number of other enhancements and bug fixes included in the release, including a patch for an issue that could cause application icons to display incorrectly.

iPhone 3.1 is free for all iPhone and iPod touch owners will be available on Wednesday via iTunes.

Check out our full first look at all the new features and functionality of iPhone 3.1.