Iphone (3G) i turned it off, now it won't turn on, please read!?

for the past month, the internet on my phone will pretty much stop working, I have AT&T. So I would have to turn it off, then back on and it would work no problems, well it did it again tonight. I turned it off for a minute or two. Then turned it back on, I saw the Apple pop up, so I left the phone on the table and went to do stuff, when I came back, I couldn't get to the home page, it did nothing, like it was never on, I tried putting it on the charger, obviously turning it back off, even synching it, taking sim card out also, nothing worked, I called the phone, it just rang and eventually went to voicemail. I have had this phone for over a year, no problems like this, i hope it "snaps" out of it, i put my sim in a blackberry, and i absolutely HATE IT. Any ideas or suggestions? Thank you!!