Belkin: Sport Armband for iPhone

The Acrylic Case gives you full access to the touch screen of your iPhone while the machine-washable Armband features a handy pocket for storage.

Belkin releases new cases and cables for the iPhone. A Sport Armband, and Acrylic and Slim-Fit Cases let you carry your iPhone anywhere and keep it fully protected. The Stereo and Mini-Stereo Cables allow you to listen to your tunes through your home stereo system or portable speakers.
 
Sport Armband for iPhone (F8Z170-KG) – $29.99
Machine-washable
Included pocket for key or earbud storage
Full screen protection and navigation access
Breathable material for maximum comfort

Source: http://www.belkin.com