"Doctor, doctor it hurts when I have to support 10 versions of IE"... errr... "Then don't that!"
Only support the last two version. Warn people who come to your site that they are using an outdated and unsupported browser. Point them to Chrome, Firefox and Opera, which are all free.
But for Pete's sake, only warn them once. Every time I visit Hotwire with an unstable version of Firefox, it reminds me to upgrade my browser with an obnoxious pop-up.
Only support the last two version. Warn people who come to your site that they are using an outdated and unsupported browser. Point them to Chrome, Firefox and Opera, which are all free.
Cut the Gordian Knot:http://en.wikipedia.org/wiki/Gordian_Knot