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I don't think you can share anything over Front Row. You can share almost anything that's in your iTunes library with Shared Libraries, which you can turn on in iTunes, under Preferences > Sharing.
 
You don't share them with FrontRow, you share them by turning on sharing in iTunes on the computer hosting the videos.

Then the other computer you're sharing to can see the shared videos via FrontRow, if it's a Mac on the same network.
 
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