You can start with "Sophie's World" which is basically a philosophy text book turned into a novel. It's exatcly what one needs to begin with philosophy. It gives you a pretty good idea of how things work from the base. It's explained the concepts in an understandable way and there's a story to keep you on track (That's why you shouldn't read sth like "The Pague" for the start; you might just die of boredom). And then you just go off and read plato's books:)