Today a client and I were working together to get his website done. As some of you know, WordPress MU for Joomla! doesn’t allow the <embed> HTML tag, which means that the users can’t embed videos. Fortunately, the client found a WordPress Video Plugin. After testing it I realized that it works without any modifications, so I added it to the list of plugins for WordPress for Joomla! and WordPress MU for Joomla!
Hope this solution works for you.