Exporting members details out of database easily

I need to implement opt-in/opt-out mailing list function in a site I’m developing in WordPress – does anyone have any experience of this?

This is not to post site content out to subscribers to to send them emails every now and again

My client may want to have a more sophisticated solution, but initially I’d like to present a system that is all under the Admin Panel of WordPress if possible, rather than use something like http://tincan.co.uk/phplist – which would require seperate administration… now if only someone could develop a plug-in to integrate PHPList into WordPress, that would be the business, and dare I say it, yet another step closer to WordPress basically being a nice, tidy, light CMS!