You can download a Kindle Reader for your PC here:- http://www.amazon.com/gp/feature.html/ref=kcp_pc_mkt_lnd?docId=1000426311
Set up is easy and you can start buying and reading Kindle editions on your PC straight away.
Works on Mac and Windows.. If you're on Linux you can get the Kindle Reader to work on wine ( with difficulty ) or with the 30 day Crossover trial or full paid version with ease.