Should be of interest to anybody interested in this, Joe Armstrongs Ph.D. thesis: http://erlang.org/download/armstrong_thesis_2003.pdf
[1] Robust Communications Software: Extreme Availability, Reliability and Scalability for Carrier-Grade Systems - Greg Utas
1) Introducing Erlang: Getting Started in Functional Programming. - Just to get an easy intro.
2) Programming Erlang: Software for a Concurrent World by Joe Armstrong himself.
3) Erlang and OTP in Action - This one seems to be the advanced book.