To direct people to watch a video from a certain point (like I did above with over the rainbow) just paste the URL, then add the desired start time in the format
#t=XmXs where the X's are the minute and second values.
EG: To skip horrible munchkins who perform for 4 min 20 sec, use:
http://www.youtube.com/watch?v=lJ10x13shL0#t=4m20s
I just discovered this and it's changed my world !!!!!!