Two of the most common hardware issues with the iPhone are failures related to the Home button and Power button. This can present as either of these buttons becoming hard to press, not reading presses at all, or they can intermittently work. If you aren't up for a Home button or Power button DIY repair to fix the issue permanently, there is a way around them by using the Assistive Touch accessibility feature. This will give you a virtual Home button and Power button that can supplement the hardware. It isn't the most ideal solution but if you need a quick one, this is it.
Curious how to enable iOS 5's Assistive Touch accessibility feature? Whether you have trouble using the physical controls on your iPhone, iPod touch, or iPad, or the controls themselves have simply stopped working properly, Assistive Touch can give you a great, software-based alternative.
If you shattered the glass on your iPhone 3G or 3GS, a screen replacement is a relatively easy repair to perform. You'll just need a few tools and a new digitizer assembly to turn your broken iPhone 3G or 3GS from broken to good as new.