I just read Timothy A. Robinson's Aristotle in Outline. It is really good. It is a pretty short book, and it is not a simple read, but it is very clear and lucid. If you want a general idea of the main points of the important parts of Aristotle's thought, you would be hard pressed to find a better book. Basically it deals with Aristotle's views on science, eg, explanation, causes, wisdom,etc. Also it has a good discussion of the soul and Aristotle on God.
There is then a good chapter on Ethics, and finally the third chapter is on politics. The book ends with a decent bibliographic essay.
I have nothign but praise for this book. If you are taking a class on ancient philosophy, or even teaching one it would be worth your while just to see it layed out so well. If you are interested in Aristotle this is a pretty good place to start.