You do not need a Kindle to buy and read Kindle books. In fact, Kindle books can be read on almost any device except a Nook. You also can access books at many libraries.
When you click on a cover, you will be taken to a page with more details on that e-short story. From there you will be able to download an e-copy of the short story readable on your Kindle, iPad, iPhone/iPod (with the free Kindle apps), and Android, Blackberry, and many Windows smartphones (again, with the proper free apps), or if you choose, on your PC or Mac computer (OS 10.5 or later) after installing proper free apps.
Kindle maintains a blog here showing you how to download apps for a number of devices.
Color is available on the Kindle Fire model and on PC and Mac computers.
After you enter your first order, Amazon will take you through the steps to complete the transaction on your credit card.
Once you have everything set up the first time, you can buy these e-short stories or anything else on that site by clicking the "Buy now with 1-Click" button. Documents will be downloaded automatically the next time you turn on whichever device you use to read.