MediaWiki is the sofware that runs Wikipedia. It is not a hosted solution, requireing a software download and isntallation. Several new packages are available now, including a Windows installer package. I have downloaded this package and installed it on my Windows XP desktop for testing. Installing it on a remote server would require more technical skills, but still appears easily done.

Initial Impressions

The installer package did everything it indicated in the documentation. I downloaded the executable file and clicked for installation. It took care of the rest.