[kennethkl]

Start with nitrous.io for a free quick dev environment. It gives you a little linux box you can play with and setup the web server. Perfect for learning.

As for language, I'll defer to the rest of the community. I'm partial on Node.js, since you really only have to learn Javascript, HTML and CSS. Everything else you can rely on your programmer knowledge. The choice is yours.

I recommend you choose a fairly simple project that interests you. No stupid hello world -- you're not completely new. Try an online tic tac toe game or something.

As for front end, I recommend you try backbone. It's barebones enough that you'll learn exactly what other frameworks do for you. It's also short enough to read to see how it works.