Hi,
I'm a Game/Performance Based Coach from Vancouver. I just created the world's 1st instructional app for a mobile device. It's based on Progressive tennis. Progressive tennis is Quick Start Tennis in the US and Play And Stay for the ITF.
Check it out at : http://www.itennispro.net/
For more information on performance based coaching check out my web site at: http://www.gbatennis.com/
Thanks!
Cheers
Neil Parker