preg_match help wanted

[SoloX]

You are a confirmed genius, my friend. It works like a charm.

Thank you very much.

--------------- Added [DATE]1260000667[/DATE] at [TIME]1260000667[/TIME] ---------------

I am greedy and back for one more and hopefuly last Q for this project.
My strings can be

PHP Code:

[media=34]filename.jpg[/media] 


or

PHP Code:

[media=34]http://www.d.com/filename.jpg[/media] 


From the first example, I got $match[2] as either filename.jpg or httP://www.d.com/filename. Lets say I put that in another variable $var. How would I check if $var starts with http or not.