I am not sure which book he is referring to by Omid Safi, maybe this one? I haven't read it yet, but I have read some of his other stuff.
As far as courses, his website is awesome. I don't know of any particular classes you can take, but there is enough on that website to keep us busy.
I actually didn't have a book in mind. Was going to see who was interested, then discuss what folks might want to read. I did think about your question though when i saw it this morning and thought Progressive Muslims by Omid Safi would be a nice place to start. It's a collection of essays by different Progressive Muslim thinkers (link below). The price is a bit steep but there are used one folks can buy for a significant discount.