I searched for iphone zoom lock, and didn't find anything, so I'll post this here. Yesterday, my iphone 3gs locked in zoom for some inexplicable reason. A little research on the web suggested that this happens sometimes out of the blue and there are two ways out of it.

THe first is to go to settings/general/accessibility and then adjust the zoom. But this is really difficult if your phone is locked in zoom. The other is to hook it up to itunes, go to the iphone summary tab and click on "configure universal access", and make sure it says neither where there are three choices - zoom, voice over and neither.

If this is redundant, sorry.