Strip away video url leaving only the video ID using php Regular expressions?

Hi I have a site which allows users to enter their details along with a youtube video link. This then gets added to a database. I want a page which displays all the submitted videos, using the Youtube API…

I’ve worked out how to pull the Videoentry meta data to create thumbnails for a video… but I want to grab the full url which the user entered from my database… run it through some regular expressions to get rid of the [B][COLOR=“Red”]http://www.youtube.com/watch?v=[/COLOR][/B]TF3fCM0c7xE(red part) and store the id in a variable. I want to then call the meta data based on the video id using the:

$videoEntry = $yt->getVideoEntry(‘TF3fCM0c7xE’);

Can anyone help me with this?

Thank you