i don't see myself as successful, but quite surprised that americans are willing to support my amaturish apps. maybe becos .99 USD seems like 50cents to us.

first of all, u need to know how to use objective-c and xcode. then u can try using the cocos2d framework to make your games. download at cocos2d for iPhone, comes with tutorials and stuff. tons of code and tutorials on the internet.

most importantly, have a good gameplay to attract gamers. good luck.