The book Building Web Applications with Erlang by Zachary Kessin, published by O'Reilly in June 2012, provides quite a bit of information about using Yaws.
In his "Functional Web" column in IEEE Internet Computing magazine, Steve Vinoski wrote a couple columns about Yaws. Both are available in PDF format:
Steve Vinoski gave a talk entitled "Erlang Web Development with Yaws" at the Strange Loop 2012 conference.
There are a number of Yaws questions with answers on StackOverflow.
Steve Vinoski wrote an article entitled "RESTful Services with Erlang and Yaws" for infoq.com back in 2008. Despite being a few years old, the advice in the article remains relevant.