I have the Sony Reader, and I've downloaded tons of free PDF files of quilting books that I've found for free.
I think there's a program that will let you use regular PDF's on the Kindlle, too.
I put a lot of patterns on it this way, too, that way if I'm out and about, I can quickly look and see how much and what kind of fabric I need.
Just about every free pattern on the web is a PDF, so its worth it for Kindle owners to get a conversion software.
The Sony will read all formats, though. So, you don't have to convert anything if you have it.
The ipad is what I'm wanting now! That sucker is awesome!
Here's a thread I started, and I listed a few of the places to get free crafty ebooks:
http://www.quiltingboard.com/t-53392-1.htm
As for regular books, this site is AWESOME! He's got tons and tons of book for FREE! Even if you dont' have an ereader you can "read" these on your computer. Its here:
http://www.truly-free.org/