Hack Request: URL Replacement

I would like to make it so when if someone posts a link to a particular site - that the link is converted to a link that I choose.

For example. If someone were to link to www.google.com (http://www.google.com) it would automatically become www.yahoo.com (http://www.yahoo.com) (if that what I chose to change it to)

I would need ot to apply to google.com as well.

I would like this to apply to in-post links, private messages and signature links - and it should apply to the archive as well.

There is a replacement hack at vB.org. It works pretty good. However you are parsing 20 posts per showthread to do it. The more terms, the harder the hit. I dunno about this one.

It would probably be better implemented in newthread and newpost. Unless it is and I recall wrong.