I was pleased to find out that YouTube finally allows for captioning and annotation of movies. Google Video has supported captioning for some time now, but YouTube's implementation is a bit different. With Google Video, you upload a text file with timestamps (.SRT or .SUB) file and Google Video creates a CC button on your video's interface that allows you to turn captions on and off. With YouTube, you set captions a bit differently. When you log in to YouTube, you go to your My Videos page, find the video you want to caption and select the Edit Annotations button next to it. Then you just play your video and pause it where you want to add either an annotation, note, or a spotlight link. An annotation looks like a cartoon word balloon and a note would look more like a caption. You can place these different elements anywhere on the video as well. Check it out:
http://www.youtube.com/v/xrgDMuhvUhM&hl=en