Smooth zoom in on hover?

Hello,

I am going to have a web page with few rows and columns of thumbnails of images like http://www.flickr.com/photos/68617652@N00/144890773/

When any image is moused over, I want a bigger version of it to appear but in a smooth gradual fashion and it should go back when the mouse is off it. Is there any such ready made script available? or can someone point me to some tutorials?

Thanks a lot.