MiraCosta’s Moodle 1.9 has a filter enabled (and Moodle 2 had it already) that allows you to use the URL of a YouTube video to embed it by linking. See this tutorial:
It used to be that we could use the Old Embed Code and toggle html for this, but the old code was eliminated by Google in December 2012, and Moodle 1.9 does not accept the <iframe> embed code.