Came across this article - Geeknuz editors tried to get an infrared scanner at the Apple Store to scan a receipt barcode from the screen of the iPhone. Alas, it failed. I guess we won't be buying movie tickets online and scanning our way into the theater with the iPhone anytime soon 
http://www.geeknuz.com/nuz/2007/07/iphone-a-no-go-.html
http://www.geeknuz.com/nuz/2007/07/iphone-a-no-go-.html