Between now and the start of summer, it will be very helpful if you start learning some of the technologies that we’ll be using.
I recommend looking at the various lessons on codecademy.com to learn about a lot of this stuff.
You’ll want to start using either Linux or Mac OS X. If you currently have a PC, I recommend setting up your computer to dual boot both windows and linux. Alternatively, if this sounds daunting, you can install a virtual machine such as VMWare Fusion ($80), Parallels ($80), or VirtualBox (free, but trickier to setup/use).
If you don’t have a favorite linux distro already, I’d go with Ubuntu.
You will be doing a lot of stuff in the command line, so you should start getting more familiar with how to use it now.
Git is a distributed revision control system that developers use to collaborate easily on the same software without emailing files to each other.
If you don’t have one already, create an account on GitHub, a site that provides centralized git repository hosting for most open source projects.
Then check out the following resources to get started on using git and github.
HTML & CSS
You’ll be building software that runs in a web browser. Which means you need to have a good handle on both HTML and CSS. There are a ton of resources out there. Here are some good ones:
Lexers, Parsers, and Interpreters