I completely agree. I don't own an iPhone, but this would practically be a killer app for me. A relatively simple concept, but I think the iPhones user interfa

I completely agree. I don't own an iPhone, but this would practically be a killer app for me. A relatively simple concept, but I think the iPhones user interface could be excellent at it, and I think it could be extremely popular within a niche. There's a lot of scope for features and development, and you could certainly charge more than $5 considering the real cost of a graphics calculator. It could also be better than current graphics calculators in some ways despite the lack of physical buttons - every graphics calculator I've ever used has seriously struggled with making a decent UI.