Here’s a round-up of the best guides online -- only making it easier for you to ditch the excuses and learn Erlang already!
In no particular order:
LEARN YOU SOME ERLANG FOR GREAT GOOD BY FRED HEBERT
Learn You Some Erlang is a great beginner’s guide, intended for those who have programming experience but may not be too familiar with functional programming specifically. In many ways, it’s the most thorough guide on this list.
Each chapter is built around a concept, from the most fundamental to the most esoteric: shells, modules, syntax in function, types, recursion, higher order functions, errors and exceptions, multiprocessing, event handlers, mnesia, and on.
Though Herbert is well aware of Erlang’s merits, he is equally wary of overzealous Erlang enthusiasts. He decided to write this guide as honestly as possible, “selling Erlang for what it is, acknowledging its weaknesses and strengths.”
(E-books and physical copies are also available.)
Getting Started with Erlang, on the other hand, throws thoroughness out the window in favor of a simple, necessity-based approach, so as not to bog you down. Keeping in its simplicity, this guide assumes you understand something about the way computers work, but you don't have to be a programming wizard.
It begins with sequential programming, then progresses to concurrent programming, robustness, and finally macros. It does not talk about local error handling, OTP, or changing code in running systems, among other things. If you'd rather just learn the essence of Erlang, though, this will get you off on the right foot.
THINKING IN ERLANG BY ROBERT BARUCH
If you’re already very comfortable with Java (or C++ or C#), this guide is for you. In Thinking in Erlang, Baruch focuses on how Erlang works given that it is not a procedural programming language but a functional programming language. So, naturally, sufficient experience with procedural programming languages is necessary in order to compare the two in a meaningful way.
And finally, from the creator of Erlang himself:
PROGRAMMING IN ERLANG: SOFTWARE FOR A CONCURRENT WORLD BY JOE ARMSTRONG
This guide – though it costs a cool $27 (and the physical copy will run you upwards of $50) -- has something the others don't. It takes you beyond the building blocks of code and actually teaches you about a program or two.
For example: you will learn how to build a SHOUTcast server, through which you can stream music to all your household computers; and you will learn how to build a full-text indexing and search engine that can index gigabytes of data for either a single computer or a parallel network.
Later, to get a handle on good coding practices, here’s a helpful guide to Erlang programming rules and conventions.