The best way to do it is VMware ThinAPP. It will allow you to run any application including IE6 on Windows 7. Even better it will allow you to run IE6,IE7, IE8 all at the same Windows 7 machine. Check out the following post and the second video in it showing IE6, IE7 & IE8 all running magically on the same machine:
[h=2]The Magic of Application Virtualization with VMware ThinApp[/h]
I hope this help some one!