I've using the NSN Mailing List in my private portal which is one of the best time saving scripts that I used.
 
The features:
Automaticly lists:
- new articles
- new downloads
- new banners
 
And the user can add any of them to the newsletter by simply choose one, and select title and link / title, description and link / full description and link.
 
It generates txt and html styled letters in paralell way.
 
I think Could be very useful for lots of users, who works hard to make good product descriptions and articles to get newsletters from that available datas.
 
Imagine: You are in the late of Friday, but need a little boost to your sales:
- get into the newsletter admin
- add 2 latest news in 1 minutes
- choose the actual best products in 2 minutes
- add them in another 2
- and add a banner to the bottom in 1
 
1+2+2+1=6 minutes for a newsletter
Manually it culd be 30-60 minutes... Isnt it?