Need Help With YouTube in a ThickBox

I am currently using ThickBox on my site and need help to make 2 things happen: PART 1: I'm trying to figure out how to use it to link to a YouTube Video. I want to have a small image on my web page that when clicked on opens up the YouTube video in ThickBox. I will need an "X" image in the upper right hand corner for the user to click on to close ThickBox after they're done. I've been trying to do it via the instructions at [login to view URL] but am just not getting it to work. PART 2: I also need help making a text link open up a web page from another website in ThickBox. The dimensions of this ThickBox would be 500 X 500 and I will need to know how to edit these dimensions in case they change in the future.