I found this item on ebay and was wondering if anybody has tried it already. Item 130288478252 Sorry I can't post a URL because I am getting this error: "You are only allowed to post URLs to other sites after you have made 5 posts or more. If you have a link to a news item or tip that you would like to share, please use the Contact link at the bottom right of this page."
Here you go: 04-08 TOYOTA PRIUS XENON FOG LAMPS lights hybrid 06 07:eBay Motors (item 130288478252 end time Jul-17-09 12:38:36 PDT)
I've seen it before when they just offered it. I haven't tried it. I'd rather go to powerbulbs (.com) to get my bulbs. Even though they're overseas, there's free shipping and their prices are very very reasonable.
I converted my driving lights to HID (true HID with the power unit) several years ago. Just do a eBay search for HID kits. As long as you know the bulb number in the stock fog light they can sell you the kit to replace it. All plug and play. If I recall it was about $150 for the kit and took me about 1 hour to install. The most time consuming part was removing the front bumper cover to mount the HID power units where they would be secure and out of the way. Everything else was very easy. Removing the front bumper is not difficult, just a lot of fasteners to deal with.
I also have converted my fog lights to HID... I used 3000k for the fog lights... I also changed the stock D2R 4300K headlight bulb to 6000k ones....