Split ipod usb cable

Hey guys

I have one iphone dock connected to a cable. That connects to my desktop. I would however like to split that into two so that I can plug the other end into my macbook. This way I can charge my iphone on the dock without having my desktop on when Im using the macbook. i dont wanna have to reach to the back of my desktop and unplug it everytime I want to charge it with my macbook.

Is this possible (without damaging the iphone) and what will I need?

Thanks a lot in advance

I may be missing the point here but couldnt you use a mains electric charger and just plug it into a wall socket, i got a full kit of chargers, mains / usb and car from ebay for £5.00, thats about $8.00.

Regards............Howard