How to send a daily digest email

I would like to send a daily digest email which contains a list of all new posts from the previous day. One way to do this is with the Subscribe2 plugin, but some changes need to be made in order for it to work with custom post types. These changes are described here:
Subscribe2 and Custom Post Types
and here:
API

I would appreciate any help in implementing this. I’m also open to other suggestions for sending a daily digest email.

This is for the Coupon responsive theme, by the way.
John