I've encountered a LOT of posts on this--some of them represent a LOT of unnecessary work. 
Here's the simple way:
1. Navigate to Administrative Tools.
2. Go to Internet Information Services (IIS)
3. If you last looked at something, Navigate to ABOVE your server name -- where it says "Internet Information Services"
4. Look to the right. You should see something that looks like this:
computer local version
-------------------------- ------- -------------
YourComputerName yes IIS V6.0
You're DONE! 