I don’t have a smart phone, but you bet all my students do! (One day soon, I’ll upgrade…) Since my schools is piloting BYOD (bring your own device) in the classroom, I may be able to use some of these apps in the future.
Another one to look at: Physics Sketchpad (also Android)
These types of apps are an awesome development! They will allow students to access real world data without the need for super-expensive sensors.