1. Getting into programming wow addons. I'm a fairly experienced developer and LUA seems pretty easy.

    I noticed the 2nd edition book is a bit old, but I suspect that a majority of the content is still relevant. Is this true?

    Yes, and I've kept the errata on this site up to date as much as possible, including any changes to the addons due to API changes/differences.

    http://wowprogramming.com/chapters/errata_2ed