An easy, step-by-step tutorial on how to add a USB power outlet was first pointed out here on PriusChat back in December 2009 and this week it has been making the blog rounds, so I thought I would take a moment to post the article from Instructables here on the front page of PriusChat. Looks like an easy mod if you want to try it out!
$0.64 (if you buy at least 2) shipped if you can wait a couple weeks for shipping. Really slender. http://www.wsdeal.com/IP151W/iPhone_3G__USB_Car_Charger_Adapter_White.ws
That link goes to your account page. But don't worry, I can't log in to it, but I can't see the product either.
wsdeal.com is focalprice's wholesale site. You need to buy at least 2, but you can get 3 for the about same price as one for this product. The OP could use the same technique and use one of the blanks, if he has one, near the dash dimmer.
I'm adding some info here even though there was a more recent thread ("Add a USB Power Outlet" 6/6/10) but it is closed. This link "www_onehalfwatt_com" has several USB circuits including ones that will alllow special devices like Motorola phones and some iPods to charge from a standard USB port. These need a special signal on one of the USB pins which standard USB outlets don't have. I incuded pictures of a USB port I added to the panel below the bridge. Cutting the hole for the port was a matter of roughing it in with a dremmel then fine adjustment with an Exacto knife. Templates for the cutout are availlable on-line.The plastic cuts pretty easily. The connector is held in with two screws. I found some small black hex head screws that blend in with the black of the power outlet and blank cover. The cable I used has a USB connector which then plugs into the USB output of my Kenwood Nav.
