If you want to learn Lua, there are tons of great tutorials on ComputerCraft's forum at http://computercraft.info/forums2.
There are also video tutorials on YouTube. Here's the first episode of Sethbling's Lua tutorial series:
I don't know what other languages you want to learn, but again, there are massive amounts of resources online. Just look for them, and you'll find them.
Another great website (or so I hear) is http://codeacademy.com. They have a large variety of online courses for several different languages.
If you're looking for general resources for logic and methodology, there's stuff for that, too. I recommend Programming Methodology by Mehran Sahami, available on iTunes. It's a Stanford course, and it's free. (You don't really need it if you're not going for a PhD, though.)