Will apple replace my iphone?

I have the iPhone 3G and today while I was at work, I went to look at my phone and it would not turn on. I have tried to plug into the computer, car charger, wall charger, and tried to reset it and nothing will turn it on. Will apple replace my iphone? any ideas what could be going on? This is the 3rd time it has done this but usually it will boot itself up after 15 min or so. It has been like this for 2–3 hours now.