Take a look at
this list. It has a section listing beginner tutorials.
My personal recommendation is
Programming Paradigms using Mathematica. It is very old, it has minor incompatibilities with version 9, and it doesn't discuss the newest features. However, it is an excellent introductions to the basics that you need to know for any version. I think it's still one of the best (free) starting points if you want to learn Mathematica well .
