Ask HN: e-mail-based Twitter monitoring?

I'm guessing someone's done it already, but if not, I might build it. Essentially, I'm looking for a way to receive an e-mail alert whenever a specific term comes up on Twitter. I know one way to do this is to set an RSS feed off of search.twitter.com, but that still requires my checking an RSS feed ... I'd like something that automatically comes to me in my e-mail inbox. (I guess I could set up an RSS-to-e-mail forwarding service to do this, but this seems like a fair amount of overhead for what should be a simple operation.)

So ... anybody have a link to a service that does this?