This has just been released, and it looks pretty awesome:
http://www.bonanza.com/background_burner

Remove white backgrounds, save with alpha transparency, and more
How does the Background Burner automatically remove image backgrounds?
Easy: It's magic! Well... it's computer magic. It uses a large number of high-tech software algorithms to analyze your image and detect line, color and focus, to separate objects in the foreground from objects in the background.
Can I clean up my image background after it's been removed?
Yes. Every once in a while, the Burned version may not have a perfect background removal. If that happens, just find the thumbnail that looks the best and click "Touch up." Then use the interactive touch-up tools to perfect your background outline.
Can it remove white backgrounds from images?
Yes, it can. If you have an image with a white background, you can run it through the Burner and save it as a PNG. This will convert the white background into an alpha layer, making the background transparent.
Why is it so important to remove the background from product photos?
If you're selling a product on a marketplace like Amazon.com or Bonanza.com, buyers are more likely to purchase when your product photo has a clean, white background. Case studies show that removing the background using a tool like Background Burner can increase sales conversion by 300%. You're welcome!
How can I use it to change the background of my photos?
While it's possible to change the background of a photo using image editing software like Gimp or Photoshop, the hardest part is removing the background in the first place. Luckily, the Background Burner does the hard part for you. Just run your image through the Burner and download it as a PNG. Then paste it on top of the new background using your favorite image editing software.
It actualy does it decent, thx cmdeal.
Looks good, nice tip!
awesome!
Freakin awesome! Thanks man
Wow that is actually a lot better than I thought it would be.
Looks good. Thanks for share.
The next version of CrazyCTR will have this feature implemented using their API.
White background with a red border works wonders for CTR.
Wow's that impressive, I tried with a few "hard" images and the result was nearly perfect.
It will save me quite some photoshopping when doing banners.