Is there a way to remove a single color from an entire picture using Photoshop CS3?

Try Select > Color Range. Then use the eyedropper to select that color. When you hit OK it should have the color selected in the image.

You can also use the Magic Wand Tool. With this tool click in the background and it should pick up the whole thing. Hit Backspace or delete. Or if you want the subject on a transparent background, you might have to go to Select > Inverse, then copy the pixels then open a new file and paste in.

Why isn't the clone stamp tool good enough? It's should remove the link or text or whatever you want, only If you are skilled enough... If the text is in the corners then you can just crop the picture and you're done.