Keep IE7 and IE8 both on single PC, single user

I prefer IETester. I just download it and can test any version of IE. Here is the link of IETester http://www.my-debugbar.com/wiki/IETester/HomePage. Hope this will help you out.

you can download IE9 from this link: http://windows.microsoft.com/en-US/internet-explorer/products/ie/home?WT.mc_id=MSCOM_EN_US_HP_SUPPORTHOME_131I1ENUS21314

after download and install, you have IE7, IE8 and IE9 in your system. just run IE and press F12 key, then click on Browser Mode: IE9, and choose IE version that you want.

you can use IETestr and test your site in IE online. but better way to have any version of IE is IE9 and change version of its local!

You can test your website with Spoon or IETester.

Or check this thread.