You lucky dog! You are about to rediscover books and have the time of your life! No matter what your taste in reading is, there is always something neat to read.
Discovering how easy it is to use your Kindle, and how easy it is to shop the Amazon store with your Kindle, it won't be long before you are overwhelmed by the sheer number of books (free and otherwise) available with just a few buttons clicks. Be sure to visit the Kindle store on your computer and look to the right on that main page. You will see a list of best sellers, both free and paid. Click each tab to browse to your heart's content. In the free area, click the "buy now" button and purchase normally... it just won't cost anything, but it will be sent to your Kindle instantly.
My advice to you? Relax and take your time. You will discover you will be able to read so much more than you ever did before. I'm not sure why, except perhaps because it is so easy to have a wide assortment of books on your device at once.
Subscribe to a Kindle blog or two so you can get the most out of your new little machine as soon as possible.
Bottom line? Just ENJOY!