This is the Wireless File Transmitter used with a 1DmkIII or 1DsMkIII. I used it a lot when I had a 1D3, but the buyer of my camera didn't think he'd used it much for his style of shooting.
I've written about it here:
http://photography-on-the.net/forum/showthread.php?t=594510and here:
http://photography-on-the.net/forum/showthread.php?t=581042 I'm asking $685 by Google Checkout (you can use your credit card). The price includes shipping to the CONUS. I don't have the box anymore, and I left the CD that came with it in the 1D3 box I sold today. But, all that was on the CD was a PDF of the manual, and you can download it from Canon, or I'll email it to you. There isn't really any software... the camera will know what to do when you attach it and you use the pairing utility that comes with the EOS utility (or download it from Canon).
If you need it, I'll also include some free technical support to help you setup a wireless connection with your computer for the first time. I'm most familiar with Vista, but I think I could muddle through the Mac setup if I had to.
Here's a pic:
-Dave-