I would avoid Philosophy for Dummies; it was written by a dummy (and a deceitful one at that). I would actually avoid all the other intros where a single philosopher describes various philosophies. In the end they all distort the philosophies they don't believe in way too much. If you looking for a good primer, then get an anthology. A collection of exerps from various philosophers will get you much further than having one guy tell you what everybody else thinks. Other than that just pick some philosophers that you enjoy and understand, and start reading up on them.
Some of the easier stuff to read is Plato, Nietzsche, Machiavelli, Hobbes, even some Marx Kant actually wrote one book that's readable. I think it was the Prolegemena. Just remember that reading philosophy isn't the same as reading history or fiction. You should be prepared to read and re-read certain things many times over, keep working until you understand a passage. And don't let the amount of time you spend on a single page bug you. If your learning, then it's productive, the number of pages covered is not important.
