Assuming you have nothing else but the iPhone plugged DIRECTLY into the MacBook read ahead. Restart the machine, see if issue is resolved. If possible try another iPhone/iPod USB cable, see if issue persists. If none of the above resolves the issue look inside the dock connector on the iPhone to see if there is any signs of corrosion dut to liquid or moisture(will look green). If this is good and it is the 1st gen phone, look in the headphone jack to see if the liquid submersion indicator has been tripped. If it is the iPhone 3G, check the indicators in the headphone jack and beneath the dock connector. If neither have turned pink, check the warranty status at apple.com/support. If you are still under warranty, bring the iPhone in to a local Apple Store or call 1-800-APL-CARE for support. The USB charge chip on your iPhone is most likely defective. Let me know if you have any other questions.