How to add subscribe button

Hi,

I know this is probably a daft question but i wanted to find out what is the best way to allow people to subscribe people to my site. Is there a good plugin that anyone can recommend that would make it easy.

I want to be able to see what people are subscribed and be able to notify them when a new post is published plus in future i would like to be able to send newsletters.

If anyone can offer any advice it would be greatly appreciated.

Thanks!