This is not going to be fully step by step guide but i'll go through the steps how i made the Ipod Touch mount quickly.
It's because it was about half year ago when i made it and i don't have enough video/ photo material to make fully step by step guide. Anyways i'll try to give you as much information as i can.
I made this mount mainly because i wanted to use GPS on my bicycle but i also found myself listening music while riding with my bike (but not too loudly so i still could hear the traffic well). The case works both in landscape and portrait, I also found out that when i removed the mount from my bike i could use it as a stand for watching movies or reading e-books for example.
I'm really happy with the final result and that's why i thought it's worth sharing.
The mount i made is usable with Ipod Touch 2G but it might work with 3G and some other version also. When you start making your own you should measure over the measurements just in case.