Here's a few links for the inquisitive to get started with.
http://www.mono-project.com/Main_Page - home page for the Mono system
http://www.tuxfiles.org/linuxhelp/vimcheat.html - a few useful VIM commands
http://www.freeos.com/guides/lsst/ - handy shell scripting hints and some general linux stuff
Mono is the open-source implementation of the .Net runtimes and JIT compiler. Basically it lets you run any .net application on linux without having to re-compile it! Awesome. Supports C# and recently, VB.
Vim is a syntax-coloring text editor and the weapon of choice for the discerning Linux coder. I highly recommend getting to grips with Vim, because it is a standard Linux tool and its extremely versatile.