Install ubuntu or mint.

Once you have that set up, it really is just a question of what stack you want to work with.

If you don't want to start using vim or emacs right away, which is understandable, there are a lot of text editors out there. You will just have to do a bit of looking around to find something you like.

The best thing you can do right now is to get a linux box up and running and then write a simple hello world in rails or django.

For bonus points, get a github account and commit your first steps to a github repository.

Doing that will give you a good bit of exposure to the shell and finding your way around the OS.