There’s not much a book could teach you that you can’t learn by playing. Get the game and start playing easy songs on easy mode, they’re so easy you’ll learn quickly how you like to hold the guitar. Then, when you find it TOO easy, try harder songs, or try easy songs on harder difficulties. Some of the games have tutorials inside, I know Rock Band 2 has a drum trainer that helps you learn drums so I’m sure there’s something for guitars too. You can also learn by watching friends. And if you are stuck on a really hard solo, go into practice mode and learn the note pattern on a slower BPM, then just keep at it. Nothing beats practice, even with fake plastic guitars :)