URL in String

I am trying to pull a link (or links) out of a text string. So if I had something like this:

textString = "This a text string that includes a link http://www.actionscript.org and I want to detect the link or even detect this link http://www.adobe.com"

I would like to be able to find the links in the text string and replace them with a single word or words that I would format to be an HTML link within a text box.

I’ve had some luck with string.indexOf, but I’m not sure how to detect the end of the link where the remaining text begins that I don’t want linked.

Any ideas?