Jailbroken iPhone/iPod touch only: Free application vlc4iphone ports the popular open-source media player VLC—voted as one of the best desktop media players by Lifehacker readers—to your iPhone or iPod touch. Apart from supporting virtually any media type you throw at it (I'd recommend using an app like previously mentioned DiskAid to get media to your iPhone), the VLC port streams internet radio, and can even stream media over your network. If you're dying to play unsupported file types on your device and aren't eager to transcode them to do so, vlc4iphone can do the trick. vlc4iphone is free, requires a jailbroken iPhone or iPod touch. The app is still rough around the edges (some playback was buggy for me, and there's no landscape mode), but it's not a bad start. Thanks Niranjan!