Where has my Safari gone?
It sounds like somehow the database that stores all the icon positions got in a jam and needs to be flushed.

You will lose all organization (but no actual data) if you choose to reset the home screen layout. This allows the springboard process to re-establish one icon for each app installed.

Settings &gt; General &gt; Reset &gt; Reset Home Screen Layout


Check out this answer - its for another app icon, but the scenario is really the same.

https://apple.stackexchange.com/a/46108/9495