Here's another massive migration/transition guide on how to move from Windows to Linux (Ubuntu).
Read it at pcmech.com (pop-up alert)
Alright, so you have successfully installed Ubuntu Linux, but now what do you do with it? You are in the right place. I am going to get you started with a guide on how to use your new Ubuntu system. This transition guide is targeted at existing Windows users and will show you how to do program installations, a little system configuration, but primarily highlight some Windows “replacement” programs for common applications you can't live without. This guide's intent is to introduce you to equivalent programs to what you are accustomed to and, hopefully, to cover a good amount of what you might want in a new install. I am basing the content on what I have personally experienced, email feedback from my installation article, questions from the PC Mech Forums, and common topics from the Ubuntu Forums. Hopefully this will answer a lot of questions you may have before you ever have them.