You can use your kindle email address to send books to Kindle Personal Document service from Calibre:
http://manual.calibre-ebook.com/faq....ails-using-app
http://www.amazon.com/gp/help/custom...deId=200767340
Edit: You can set your Kindle email address and approved email addresses here:
https://www.amazon.com/gp/digital/fi...?#pdocSettings
My manage my kindle page seems to have reverted to the old format. Just look for the Personal Documents settings if the above link leads you astray.