Email Alerts for Updates

Hello,

I am trying to find a plugin that will allow site visitors to register to receive email alerts when new content is posted to a site. I need the user to have the option to select a value of a custom taxonomy that they want to receive the updates from as well.

If anyone knows of a simple plugin that will allow me to put a section on my site that simply has a field for email and a select feature for which user group they want to receive the alerts from and a register button, I would really appreciate it.

Thanks