Could someone share with us how to save this clip to our computer before it disappears?
There are numerous free programs you can download off the internet which allows you to download YouTube videos. Just be careful about WHERE you get them from. Try to find a credible download site. Then, be careful, in terms of check boxes and various options and offers, while in the install process, so that they wont stick any unwanted junk on your system along with the program.
In any case, here is what appears to be the same video from YouTube...
Admiral Ret James Lyons on Islam as a threat doctrine (3:52 min)
https://www.youtube.com/watch?v=XBgi7r1hEsA
Well covered on FR closer to when it happened:
http://www.freerepublic.com/focus/search?m=all;o=time;q=quick;s=lyons
At the very least, email it - to a friend and yourself. When you get it you can save it.