New here and starting my project

i saw a guy with a bike on a bicycle the other day. And it gave me the motivation to do it my self. Im fairly new to the whole mechanic stuff but im not completely lost either. I just want some guidance on this project and alot of you seem like you've gotten a good amount of first person experience. well this is what i got to work with.
http://s1203.photobucket.com/albums/bb396/nestor1320447/?action=view&current=0803111220.jpg

hanks those links cleared it up a bit but im sure ill stumble upon more problems once i start working on it
i was also wondering if theres a way to disengage the pedals when the motor is running because i still wanted to be able to use the pedals at some point (like if im low on gas or something or wanna)