Q:

RSS to email daemon

I need a daemon that turns RSS into email. 
It should have an API so I can programmatically tell it that user john@doe.com has subscribed to http://example.com/myfeed.xml. 
Frequency should be configurable, i.e. I don't want it to send one email per rss item, but group it and send daily emails. 
It should also allow some sort of templating (XSLT or anything) to transform RSS into HTML.
I think these are fairly common requirements so probably someone has done this already... and I don't want to incur NIH ;-)

A:

http://rss2email.infogami.com/

