Stop Youtube from displaying related videos once playback of the initial video starts

To stop displaying related videos we can add a parameter (rel=0 for stop displaying) to the url of the embedded code provided by you tube. See example below

http://www.youtube.com/v/u1zgFlCw8Aw&fs=1&rel=0

For complete list of parameters check the following Google API site:

http://code.google.com/apis/youtube/player_parameters.html