How do I figure out the position and size of a single sprite in a sprite sheet?
In the book (breakout game chapter 3) ben writes this

GamePaddleRect = new Rectangle(39, 1, 93, 23),
            GameBallRect = new Rectangle(1, 1, 36, 36),
            GameBlockRect = new Rectangle(136, 1, 62, 27),
            GameYouWonRect = new Rectangle(2, 39, 92, 21),
            GameYouLostRect = new Rectangle(105, 39, 94, 21);

// Make sure paddle stay between 0 and 1 (offset 0.05f for paddle width)
            if (paddlePosition < 0.05f)
                paddlePosition = 0.05f;

Ok, now ive got the coordinates out of the code and i can use them.
But how can I get these values out of the image itself?
Is there a program for this, or do you just know them if you created the spritesheet yourself?

i was JUST asking myself this very question.. hopefully we can both get an answer.

If you have Photoshop, you can get the information in the info panel by selecting the area with the marquee tool. You should set your ruler grid to pixels. You could also do it by trial and error. Once you have the dimensions for the ball, the images are laid out in a rectangular array, so you have the "Y" dimension for the first row, and the starting X coordiante for the next item.