Put the show notes in PDFs that will come in the iTunes feed (now that iTunes is a PDF organizer and viewer).
Personally, I'd prefer to get the links and stuff in the RSS feed for the podcast. Then I could subscribe to it in my RSS reader--which is where I go when I'm looking for interesting links anyways--and find out all about the day's topics.
I hate email newsletters as a general rule anyways, which is why I've never signed up for the BOL newsletter. I don't even like the "Google Friends" emails. RSS is much better!