http://www.microsoft.com/Downloads/details.aspx?FamilyID=21e...
http://www.microsoft.com/Downloads/details.aspx?FamilyID=21e...
For my own system I used MSDN to get working installs of XP on my Mac in VirtualBox.
You also need to convert the VHD to VDI. I've done this on Mac using Q (http://www.kju-app.org/) and these simple commands.
/Applications/Q.app/Contents/MacOS/qemu-img convert -O raw -f vpc "input.vhd" temp.bin
VBoxManage convertdd temp.bin "output.vdi"
Download it here:
http://www.microsoft.com/downloads/details.aspx?FamilyID=8e6...
You're going to need to find a way to test on a real version of the app. Xenocode(.com) used to have sandboxed versions of all the browsers available, which was perfect, but they've since removed the page. So now the images provided by MS (referenced in parent) are your best best.
I still think it's invaluable - rather than setting up three separate VMs, I can just have one on IE6, and launch 7/8 as needed (I usually just save-state at that point so I'm not constantly launching them).
I think the howto to convert them I found on stackoverflow or something, can't remember now.
I have XP_IE6, XP_IE7, XP_IE8 working fine.