Lots of time I like to link to YouTube videos even though there is only a small portion of the video that is worth linking to. I usually end up adding comments near the video link telling people the time frame to look at. There's no a much easier way to link to YouTube videos where you want to show people a specific section of the video.

Go to Splicd (http://splicd.com/), give them the link to the video and enter the time range you care about. They create a piece of HTML that you can embed in your pages to link to the video so that only the specified time range is shown and played. Much easier.