If you haven’t noticed, Apple has changed the screws on the iPhone4 so you can’t open it. A company has decided to make the proper screwdriver available at a cheap price – $9.99. If you want to open an iPhone4, get it, probably the cheapest you will find it.
Link for tool
http://www.ifixit.com/iPhone-Parts/iPhone-4-Liberation-Kit/IF182-019
Link to article
http://www.wired.com/gadgetlab/2011/01/apple-is-screwing-your-iphone/