Source code download https://www.erlang.org/downloads
One-click install https://erlangcentral.org/downloads/
Install with kerl https://github.com/yrashk/kerl
Emacs: Emacs has a feature-rich integration with a wide array of tools and utilities for working with Erlang.
Vim: Use the vimerl plugin.
TryErlang.org: an interactive in-browser tutorial to help you get to grips with the basic syntax and mechanisms of the language.
IntroducingErlang.com: get Erlang installed on your system and write a non-trivial working application in 30 minutes.
Learn You Some Erlang: a free online book for beginners that guides you through the essentials in Erlang.
Open a terminal and fire up Erlang (by simply running `erl`) as you read through the site. Test out the code examples in the book, and read through the explanations. This is one of the best ways to learn Erlang.
Once you have started to get to grips with the more complex and glorious features of Erlang and OTP, pick up a copy of Erlang Programming for reference. You might also be interested in learning about rebar: a tool from Basho (the guys behind Riak). They have provided a great guide to getting started with it on the rebar wiki.
Getting involved in the Erlang community is a great way to both improve your own skills and techniques and encourage the others you interact with to improve theirs. A great place to start is the erlang-questions mailing list, or by perusing the unanswered questions on stackoverflow.com. You can also try our very own forums here at ErlangCentral.org. If purely electronic interaction doesn’t quite cut it for you, there are also the Erlang Factory events.
For some more advanced testing techniques, you might wish to check out PropEr: an OSS property-based testing tool. If you’re looking for something more commercial with full support, you should also look at QuviQ’s QuickCheck.