Swiping images across the screen - iPhone

Hi Guys,

I'm trying to find a good way to setup a bunch of images in landscape across the screen that the user can swipe through with their finger.

I'm not sure how to implement this at all, for example how do you know what direction the user has swiped the screen, if the image has not been dragged with enough 'force' it needs to bounce back, the whole image should fit the screen - you can never be left with half an image on screen etc.

Thanks , any help would really be appreciated :)