ok - not sure if i've read this somewhere or if my brain's not working from lack of sleep... but, how do you deform an object without changing it's actual size?

so, i need to model a number of sheets of paper, but they all need varying degrees of curliness to them... i have a flat piece of paper model (took me ages to make :p) that I want to change without changing the size of it's actual dimensions...

would i smooth bind it to some joints....? er...not sure if i'm making much sense.