just moved site from wp.com to 3rd paprty hosted .org, youtube links broken ?

Hi,

I just moved a site from a wordpress.com hosting to 3rd party hosting using wordpress.org, got it all working fine but the youtube links now dont work they come up in the posts as
[youtube http://www.youtube.com/watch?v=QJm97o-4qYI&w=500&h=315%5D which is visable to the public,

is there a way that i can mass edit these to make the live again ?

I would do it by hand but there are over 2000 blog posts

thanks in advnace.