Iphone "drawing too much power"

Had my macbook for 7 months and my iPhone for 4 months. Everything has worked OK with my macbook and Iphone 3G until now. (Apart from the speed issue with iOS 4.0). Then yesterday the phone could no longer connect to Itunes and I got the following error message:

"Because a USB device was drawing too much power from your computer, one or more of your USB devices have been disabled"

My trouble shooting so far:
- I have connected Iphone to other macbook = same problem
- I have connected my Ipod classic to my own macbook = no problem and syncs well
- I have tried different cables with my iphone = same problem
- I have tried same cable with ipod and other macbook = no problem with cable
- I have restarted the macbook using sleep, restart and shutdown = same problem
- I have shut down started the macbook in safe mode = same problem
- I have shut down and started the macbook using Command Option+RP = same problem

Further to the above, I am aware there is quite a bit going on behind the scenes these days. For your information, the problem started before I had the chance to update to iOS 4.1. and it happened before I updated to Itunes 10 (or whatever the version that came out yesterday is called).