Python is an excellent language for a beginner to learn. You can grab it from here; it's very easy to install. There is also the excellent, free, book Learn Python the Hard Way which assumes no prior Python, or programming, knowledge.
Ruby is another great language for beginners which you can get here; it's just as easy to install as Python. There is also a Ruby book written by the same guy, and in the same format, as the Python book which is also free: Learn Ruby the Hard Way.
Personally I think you cannot go wrong with either language. If you were to press me to make a decision about which language I think would be better to learn I would have to go with Python, but only by a small margin.
And as a bit of a side note I also recommend using Sublime Text for writing languages like Python or Ruby. It has an excellent GUI and syntax highlighting, and is able to compile and run your Python and Ruby applications within the program itself by simply pressing CTRL+B (which is far more convenient than having to open a command line and running the program from there).