You probably know GreaseMonkey,
the user-script and power-to-the-people extension for Firefox. Now the
power to change comes to that other browser, too: Enter GreaseMonkIE.
Many scripts work, except for those that use Firefox-specific code,
and some using XPath. In general, it’s far less comfortable to use
GreaseMonkIE – then again, using IE is less comfortable already, so
people might have gotten used to it.
GreaseMonkIE requires the .NET framework.
Update – GreaseMonkIE is no more.
Trixie works. It can use greasemonkey scripts too. I think it’s been around for a while.