Someone stole my iphone need some help please?

[Raphael]

So i had a iphone that i used as an ipod touch. I always left my facebook, twitter, instagram, etc, account on. I need to find out a way so that if they do end up breaking my pass code, they can't use any of the apps. Thanks!
It's not just the apps i care about it's the fact that i have information on those apps. I just don't want someone going into my Facebook and posting things claiming it's me. Also i don't have ICloud. My Iphone was a 3G and it didn't have Icloud installed. Also how could i get my Apple account off the phone?