What We Like: 
PulseK is perhaps the best and simplest way to track Klout scores.Track just yourself or as many other people as you like. Get a quick overview of how your Klout score changes from day-to-day, or drilldown to get detailed information about your influence and what topics you're an authority on.
API: 

http://developer.klout.com/ 

Application URL: 

http://itunes.apple.com/us/app/pulsek/id500577289?mt=8

Platform: 
iPad
iPhone