I just read the nice thread about Amazon's amazing service re:Kindle. I thought I would share a source (totally free and legal as far as I know) for free books for Kindle. There is a Web site called pixel of ink (pixelofink.com) that sends a list of free and reduced price Kindle books every day of the week. Clicking on a book takes you right to the Amazon site, so there's no funny stuff going on. Pixel of ink just creates a list of the books Amazon is "selling" for $0.00 on any given day, as well as those that are "on sale" that day.
I have "purchased" more than 100 books for my Kindle this way. There are all sorts of books listed, from vampire mysteries to cookbooks. If you are tired of paying for all your Kindle books, check it out.
FYI -- I have no involvement or financial interest in the site, I just like to save $$$$.