no I have dark brown hair and I died it caramel without bleaching, you only have to bleach when you're dying your hair a crazy color like pink, red or like blue. But just warning you dying your hair is really damaging, I regret dying my hair.
Yes...bleaching your hair to the correct shade for dying it lighter isn;t easy..it tends to stop at orange shades.<br />
Get it done in a salon. <br />
But once you start mucking about with dramatic colour changes keep in mind of the on going care<br />
... (about every 6 weeks) of dying the roots.
If your hair is dark and you want it a light color, the hair needs being bleached or else it won't catch. Many professionals dislike bleaching and this is when you got to do it yourself. Bleaching is not great for the hair, it damages it.
In my experience with changing hair colour, always best to leave it to the professionals. I would go to a hairdresser