user agent string utility

I have a program on one of my servers (a website activity reporting program - webtrends) I am stuck at an old version because they raised their prices to an prohibatively high level. I plan to replace this program with something this year but not yet.  
 
This program requires internet explorer and complains if the version is 7 or 8 (anything but IE5 or IE6)_... in fact it will not allow the user to see the site...  When version 7 came out microsoft released a "User Agent String Utility" that would temporarly launch an internet explorer window disguised as version 6 which worked fine.
 
Now that microsoft has started pushing out IE8... I need to find an equivalent program to have some customers run -- i have not seen microsoft release it yet.  I'm wondering if the "user agent" that the browser reports can be changed either thru the menu or thru the registry.... any idea on this...
 
or have any idea where I can find an updated "user agent string utility" -- no rush, but if you come across something, let me know