If you've been living under a rock for the past, oh, two years and aren't sure how to accessorize your iPod, iPod Garage has got you covered.Starting today, the site is offering a free, downloadable book "PRONGBOOK: a three-pronged guide to protecting, listening to, and enhancing your iPod."The book will cover all three current iPod models and claims to be a "start to finish guide on how to determine which specific accessories are right for each iPod user and how those accessories can best be integrated into the user's experience."Useful or you get what you pay for? Well, that's up to you. Actually, we snottily scoff at it, but it may be just the thing for the new, somewhat non-technical iPod owner.