2nded.  IMO, Erlang the <i>language</i> is really really simple and easy and the basics can be learned in a few days, though it helps to have been exposed to Lisp, PROLOG, or various functional languages.<p>What I find far more challenging is catching up with the myriads of libraries &amp; frameworks that are used to build real applications.  Oh, and finding compatible versions of these can also be an unwanted adventure at times.