If you have access to a windows box, here's a better solution: Install IE10 and use the dev tools (F12). there you can set browser emulation to IE 7,8,9,10.
doesn't include ie6, but not many people still use it: http://www.ie6countdown.com/
doesn't include ie6, but not many people still use it: http://www.ie6countdown.com/
Which means you are likely to be fixing rendering issues and buggy behaviour in the emulated version that don't exist on the real thing, and more importantly missing issues that are evident in the real browser but not on the emulation.
It's a cognitive dissonance, you are testing a browser stack your customers won't be using.
Virtual machines are practically a better solution, though it gets into slighty murky territory when there's a lot of JavaScript magic going on. At that point, nothing really beats a native browser running on native hardware.
[1] http://alexjmackey.wordpress.com/2012/10/19/how-accurate-ie-...