you can go to itunes, then go to file-->add folder to library. then select the folder with the converted file and open it. or, you can just click and drag it into itunes. ;-)
If you get any problems with that, make sure you shorten the name of the file to something simple, as iTunes seems to reject videos with large filenames. (note: you can always revert the filename back to what it was origionally, once you have added the video into iTunes