Reg Expression Help Please

Ok, I need a hand. I can't seem to get the regular expression to work quite right.

I need a regular expression to match this:

www.something.com or
http://www.something.com

Along with that I need it to match if there is any trailing subfolders so:
www.something.com/here/ or
http://www.something.com/here/

Make sense?

Thanks in advance to the person that know more about regular expressions than me.

 

BUMP...no one have the reg expression for this?

 

I saw many examples for this! Wait let me google.

Back.
Use this at google:
url php regular expression

and you will find many

 

is www.something.com a fixed value or do you want it to match any domain?

 

Thanks for answering.

I found a solution over at: http://regexlib.com

The regular expression that appears to work so far is:
(http:[\/][\/]|www.)([a-z]|[A-Z]|[0-9]|[\/.]|[~])*