Maybe I’m the last person on earth to figure this out, but I have an old-style Kindle (read: the kind the dinosaurs used to read books about eating each other) and I thought my only option for reading PDFs on it was to, you know, drag-and-drop said PDF onto my Kindle drive when I had it plugged into my computer. The good news is that it works, but the bad news is that the formatting is all kinds of wonky, and the print is tiny. Sometimes I get e-books sent to me as PDFs and I really wanted to be able to put them on my Kindle and read them without a magnifying glass.
So I did some research, and what do you know—there’s actually free Amazon software that will automagically convert your files to Kindle versions. (Did you know this? How did I not know this??) You can download Send To Kindle for the Mac or for PCs to get started. You’ll need to go into Options to selection conversion, and yeah, the final result is not as nicely formatted as an actual Kindle book, but at least you can read it.
Source:
http://wantnot.net/2013/01/12/read-pdfs-on-your-kindle-yes/