I would just use
Dropbox It's alot easier to download your ebook library that way. I just drag and drop files from my PC into my Dropbox and it's uploaded then I just use the Kindle browser to log into my Dropbox and download whatever Mobi book I need at the moment. You get 2GB at signup which is plenty and you can get more by doing various things but it's free to use.
If you use my
referral link We both get 250MB extra once you install the program on your PC. Alot of us here use Dropbox and it makes owning a Kindle even better. It's completely Free and easy to use.