I've been reading the 21st Century Physics one. It's a very readable explanation of some of the things I never got to in College. I think it's great that more and more educators are doing things like this and releasing them for all to read. Creative Commons ftw.
A tip for kindle owners (or future kindle owners), make an account on amazon using an american address (just don't buy physical things obivously), then buy gift cards and redeem them on that account. You'll then be considered american.
Most (all?) of the free books are not available outside of the US because Amazon has different wireless deals elsewhere, with different cost structures. In some (most?) places, Amazon would take a loss on the wireless costs for free books, so they replace them with alternate versions which are minimally priced to cover the wireless costs.
I'm in Canada accessing it using my regular IP address, and I managed to get the Advanced Probability and Statistics book transferred to my 3g kindle without a hitch.
Kindle for non-.txt files is pure scam. I can't read most pdf files I tried.
Want proof? Download the very 1st book recommended on the article. Look at the very first formula on a non dx kindle.you can't read it. Not even in landscape. Not even with zoom.
Now get apdf with two columns. Like the car manual I bought. you have to zoom to read. But you can't make one column fit in the screen. It's not lack of space. Theres lots of white space, but the pan will skip just more so that you can only ever read half of each column at a time. Just patetic... Btw that's how adobe treader for nokia symbian works. You get the idea.
http://www.amazon.com/exec/obidos/ASIN/B0042XA2Y0/antoniocan...
http://www.amazon.com/exec/obidos/ASIN/B0042XA344/antoniocan...