It is also free.
After learning the syntax, check out these chapters
* "Designing a Concurrent Application" http://learnyousomeerlang.com/designing-a-concurrent-applica...
* "Buckets of Sockets" http://learnyousomeerlang.com/buckets-of-sockets
* "Distribunomicon" http://learnyousomeerlang.com/distribunomicon
* "Distributed OTP Applications" http://learnyousomeerlang.com/distributed-otp-applications