It's not in the amazon store. You have to root your Kindle to allow it to install the Google play store. There's tutorials on YouTube , just search "how to root Kindle Fire"
You dont need to root your device, you can either just download and install the latest apk from elsewhere.
Or go to 1mobile and download there app, there is hundreds of applications on there, including Tapped Out. Its how I play on my kindle fire hd. http://www.1mobile.com/app/market/?cid=9
About The Simpsons Tapped Out General Discussion
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