I had this idea in the back of my mind to program a standalone guitar tuner, one that automatically detected the guitar's pitch. This concept was nothing new because practically any tuner can help the beginning guitarist do this quickly (the Boss TU-80 is one of my personal favorites because it beeps when your guitar is in tune). However, it seemed that all of the online guitar tuners played a static tone and give the user no audible or visual feedback. It annoyed the hell out of me, enough to aspire to that programming height.
The Guitar ToolKit is a great guitar tuning program for the iPhone, and it beat me to it. Guitar ToolKit is awesome because it's tuner will give you the exact feedback you need for tuning. It's unbelievable. I wish I could have been the first to create it. I guess this means I will be recommending it to everyone instead.