Actually, I just picked up "Exercising the Penis" by Aaron Kemmer.
Just the prices on Amazon - some people will try to rip you of for several hundred dollars, but if you find a good supplier, you can pick it up for $10 as I did.
Yes the info is freely available on all the typical sites, but if you're looking for a detailed linear instruction, I would recommend spending anything less than $20 for this book.