Need multiple email address/user

I'm looking for a way to let me users have more than one email address. When I contact them or send out newsletters or mass mailings, they want to receive it at more than one email address.

I looked at addresses extras, which doesn't seem to do anything but provide information, and views mail, which I can't for the life of me figure out what it does or how it does it.

This sounds like a pretty basic capability, and I'm sure someone must have dealt with this before, but I didn't find any solutions for drupal 6, and only an incomplete one for drupal 5.

Does anyone know of a good solution? Thanks.