Duolingo is the most popular way to learn languages in the world. Best of all, it's 100% free!
Memrise has their own official MSA course now
http://www.memrise.com/courses/english/arabic/ - There are 7 sections.
Pretty good as a starter or if you're eagerly waiting for Duo to get an Arabic course :) I do recommend you spend some extra time learning the script though.
301 year ago