Learning Lua / Making Addons
 

Would this new programming book be a suggested start? I do have extensive knowledge in XHTML, CSS, XSLT and XML and decent knowledge in JavaScript and PHP. Also would there be any other suggested material to look at? Looking forward to thoughts. :]

Programming in Lua for the language itself.

Interface Customization on wowwiki for World of Warcraft specifics.

Reading existing addons code is also a good idea.
Especially by recognized / accomplished addon authors.
You will find addons by them ranging from the overly simple (due to scope),
to the complex.

The book would also be a nice complement yes.

I personnally like lua-users http://lua-users.org/wiki/TutorialDirectory

The World of Warcraft Programming book is a very good start if you already know basic concepts of programming (like you do with knowing PHP).

Programming in Lua and the Lua Reference are perfect for a quick online research on Lua semantics and functions.

Both together should bring you a long way ;)

wowprogramming.com has a very comprehensive API reference available, as well as a number of tools like an online Lua sandbox for checking bits of code.

I'm learning to program addons using "Hacking World of Warcraft" and "World of Warcraft Programming".

I chose them because I learn well from source books, like to have shelf references, and know that the authors are respected members of the addon community with good histories and solid knowledge. I respect the publishing firms as being reputable in computer reference materials.

That said, everyone learns at their own pace and in their own way. I think that these are excellent references, but if you can only learn from online tutorials and splash-wikis, then go find them and program madly!

I find both at Amazon, most large book retailers will carry or offer to order.

I don't know all of the languages you listed, but I don't think any of them are really procedural languages. Do you know things like for loops and the like?

If you have a good grasp of basic procedural programming concepts (loops, events, conditionals, functions) you probably don't need a book. Lua is not a hard language to learn at all unless you're learning from scratch. You can get by making simple addons and gradually expanding your scope, looking at increasingly dificult addons for inspiration when you get stuck.

If you know php and xml lua will be easy for you. Get the book World of Warcraft Programming, it's a good read.