From Omar Shahine's blog post entitled Inline Search for Internet Explorer we learn

This is simply a must have add-in for IE. For those of us that used the FireFox Find feature and were like "OMG", you can now have the same thing in IE. 

You can see in the screen shot below how this works:

[Source: Paul Thurrott's Internet Nexus]

As an Emacs user, I've grown used to having inline search as a feature and often get frustrated when the application I'm using doesn't support its. It's great to see this feature added to Internet Explorer. I just downloaded it and it works great with the most recent beta of Internet Explorer 7. Give it a shot.

By the way, Jeremy Epling and Joshua Allen who both work on the IE team also told me to check out http://www.ieaddons.com if I'm interested in tricking out my Internet Explorer install. I've added the site to my bookmark list and will check it out later today to see if there any other interesting IE extensions I've been missing out on.