Supertask has Seedio (iTunes Link) for the iPhone and iPod Touch in the iTunes App Store for FREE for a limited time.

Enjoy music together: Seedio connects multiple iOS devices to create one perfectly synchronized loudspeaker. Play songs from your Music Library and from YouTube (more sources to be added in the future). Broadcast (seed) music to other iOS devices over Wi-Fi for perfectly synced group playback. Pump up the volume by adding more iOS devices.

Connect iOS devices to active loudspeakers for the ad hoc outdoor party and leave heavy equipment at home. All you need is a couple of iOS devices running Seedio and a Wireless Network – a Personal Hotspot set up on one iOS device is fine!

Use Seedio as a wireless headphone splitter to broadcast and share audio to a group of colocated listeners in quiet environments – playback is simultaneous and synchronized on all devices.