Microsoft Makes Testing IE6 and 7 Easier
davidmcg writes "Finally, Microsoft has made steps to make testing IE6 and IE7 easier for Windows users. Previously, you had to pay for an additional Windows license to legally run both versions of IE for testing purposes. Now Microsoft is making available free Windows XP/IE6 images available for VirtualPC (also free as MS is competing with VMWare). This means that you can run IE6 in a virtual machine while running IE7 on your host machine. The drawback is that the download is set to expire April 2007 ... although we are promised new versions will be released. What Microsoft doesn't mention is that Virtual PC also runs on Windows 2000 (and IE7 doesn't). Therefore it's possible to install this Windows XP VPC image on your Win2k machine. You can then update IE6 on the XP image to IE7, testing IE7 without upgrading from Win2k. This is all-around excellent news for web developers."
No the IE tab extension is not specific to IE6 and will therefore run IE7 in a Firefox tab if IE6 is installed. There's various hacks to run IE6 and IE7 side by side and they're not approved by MS so it's possible that you could be running IE6 with some IE7 libraries and then the result would not be a perfect IE6 install and some things may differ.
I just learnt this from the German IT news site heise.de http://www.heise.de/newsticker/foren/go.shtml?read =1&msg_id=11722667&forum_id=109109
On following sites you can test your webpage via an online renderer
For IE 6 and 7: http://ipinfo.info/netrenderer/
For Safari: http://www.danvine.com/icapture/
For Firefox and many others: http://browsershots.org/
hth
Prior to the release by Microsoft of this VM image I got round the legal requirement to buy an extra XP licence by running XP with IE6 and running the free to download (at the time) betas of Vista in a virtual machine for IE7 testing.