Looking for inline for advertising scripts

I have seen these scripts that go through what others write on a forum and add advertisment links. I think the most popular is probably Amazon. Here is another company that uses it: http://www.vibrantmedia.com/whatisIntelliTXT.asp

I run a micro stock photography forum website and I want it to add an link when people use one of the agencies name in their post (iStockPhoto, Shutterstock, BigStockPhoto, etc)

Anyone use this type of stuff or know of a script (free or commercial) that can go through my text and add advertisements based on a pattern match?

Thanks!