Robin Good: The DSLR Filmmaker Toolkit is an iPhone app which allows you to organize, track, set and measure your shooting-related tasks right from your iPhone.

Key features include:

Digital SlateShot LogViewfinder (can emulate different HDSLR cameras)Depth of Field CalculatorDaylight TimesDigital Level 

Uncovered by:  

More info at: 

Available in the App Store: $7.99

Via Robin Good