Have you ever struggle measuring things around? Did you ever though of the idea of just using your iPhone to make this task even easier? Well if you did then this application is what you have been looking for.
Sonar Ruler is an experimental application that uses echoes to measure distances with your iPhone. According to the description "it uses the same principles the dolphins use to find food".
You should probably be asking your self how does this work? Well to answer that question this application sends short pulses from the speaker and it measures how long that pulse take to bounce of something and return to the iPhone.
Sonic distance measurement up to 60 feet
Set Units to feet, inches, or meters
Custom saved settings for measuring in different environments
If you like to measure things around then you should try this it looks really great but remember this is just and experimental app but "it can be quite accurate".
The application only cost $0.99 you can get it here(link opens up iTunes)