I wish I had this app installed on my iphone when it was stolen a few months ago.
The iGotYa app lets you know who’s trying to snoop around your iPhone by snapping a photo of whoever enters a wrong lockscreen passcode. The photo is then emailed to you along with your devices current GPS coordinates. It is such a simple idea, and is a great use of the front facing in the iPhone 4. The only downside is your phone needs to be jailbroken for it to work.
iGotYa is priced at £4–though there is a free ten-day trial available–and can be found in the BigBoss Cydia repo.