A few weeks ago, I did a tutorial about how to change your user agent in Google Chrome/Chromium. That tutorial was very informative imo, and this time around I am going to cover how to change your user agent in Internet Explorer 8 and 9. Be careful to not interchange user agent with the rendering engine, though. You can change the rendering engine version in the F12 inspection tools at the top right.
There is no easy way to change IE's user agent, so I found this extension/add on that does the job for you. Otherwise you would have to fool around with the Windows Registry via regedit, and who wants to do that? Certainly not me, and if you do something wrong you could seriously damage your computer.
You can also add a toolbar button for UAPick, and that is shown below.