Can users create/copy a cookie?

I was wondering if user's are able to copy a cookie stored from one computer to another? Ex: I will copy the cookie which keeps me logged-in or "remembered" in a website to another computer so that using the other computer I am able to "log-in" automatically? I am wondering if that was possible then what would be the best way to handle that security issue?

thanks

I don't think that this is possible, but we can check it out. Send me an email with your cookie of this site (it will give me access with your username, but I can have this access anyway :) ) and we'll see what happens...