Sending a "welcome message" to each newly registered user

What I need is a way to send a "welcome message" to each newly registered user to explain how to use the site, make them aware of policies, or just say hi. I can't believe that this feature isn't native or that there isn't a plugin already developed for it! Did I miss something?

If someone could develop this for 1.6, I'm sure the community and I would be extremely greatful!

Thnx!