Pupil Picker uses your iPhone's Address Book to randomly select students while you ask your students questions or check answers. You then can record correct and incorrect responses. After you have finished the lesson you can quickly send yourself an e-mail to view the results for later use.
I can't really vouch for it because I have never used it but I was intrigued by the concept. It is also has a great backstory of how the program was developed. The Kindergarten teacher who developed it taught himself programing in a short amount of time and then created the program. Let me know if you use it and and how you like it.