There are many video plugin for WordPress. My recommendation is Flash Video Player.

It is convenient to add youtube video by using it.
[flashvideo filename=http://www.youtube.com/watch?v=sSHVQ2m1Bdk /]
Here are some useful links:

Please refer to the comprehensive list of options for a complete list of what is configurable for this plugin. Read the F.A.Q. if you’re having trouble. Chances are your question has already been answered. Also check out the sample color combinations for the player to help get you started. Finally, there is a forum available for any questions, problems or feature requests that might arise while using the plugin.