I'm looking for an existing semi-decent software that can highlight multiple search terms simultaneously, using different colors, and show the count of each matching search term. I also need an easy way to apply the same keywords to different texts.

**EDIT**

To explain with an example, this does more or less what I need:
<http://janosgyerik.github.com/highlighter/>

I put this together quickly because a friend of mine needed the functionality under time pressure. I am quite tempted to build on this, but I don't want to reinvent the wheel. Such tool seems to be a pretty common need to me, like my friend I too often find myself wanting to do multi-keyword searches. I believe something must already exist out there I'm just unable to find it. I don't want to reinvent the wheel, if there is such existing software, I am ok with throwing away my work so far and use what exists. If there is no such software, then I'll be happy to continue hacking at this example above, I just really don't want to foolishly reinvent the wheel.