Sure, if you find the youtube vedeo you want and look at the address:
Code:
http://www.youtube.com/watch?v=R7jG83IFGK8
You just need the number after the v=
So for the above you just need: R7jG83IFGK8
Then you click the Youtube button or type:
PHP Code:
[YOUTUBE][/YOUTUBE]
Then put your number between the tags like this:
PHP Code:
[YOUTUBE]R7jG83IFGK8[/YOUTUBE]