Handbrake. Drag and drop the the video file (in explorer) to %UserProfile%\Music\iTunes\iTunes Media\Automatically Add to iTunes so that it will be automatically added to iTunes.
Open iTunes and you should find the video in your Library in the 'Movies' section under 'Home Videos'. Right-click on the video in iTunes and select 'Get Info'. Select the Info tab and type in the name of the movie in the 'Name', the movie studio (e.g. Sony Picture, Warner Brothers, Universal Picture) in the 'Artist' and the year in the 'Year' box. In 'Genre' select the appropriate kind in the drop down list.
Click on the 'Video' tab and in the 'Description' box enter the summary of the movie (you might want to copy/paste it from the imdb or from the itunes store movies section). Click on the 'Sorting' tab and enter the movie name in the 'Name', movie studio in the 'Artist' and movie name again in the 'Album' box.
Click the 'Options' tab and under 'Media Kind:' select Movie (so that the video will be placed under 'Movies' instead of 'Home Videos' in your iTunes Library). Click on the 'Artwork' tab and add a picture file of the movie and click 'OK'.