Either of the two Mac's you mentioned will do nicely,
Charge what you like for the app. If it is good, it will sell. If not.............
Books/On line would be a good place to start learning X code /Cocoa
It takes anything from 30 minutes to 30 months to develop an app.
Good luck, see you at the app store
I am looking to develop a Iphone/Ipod touch app. I was wondering what age are you allowed to develop a app and submit it to the store. What type of apps are allowed(I know apps are not allowed to work in the background). Also, if i bought the $99 SDK would i be able to charge people for the app and still make money?Which is better for developing a app a Macbook Pro(the 15 inch 2.53ghz or the 17 inch 2.66ghz?) or a Imac(the 24 inch 2.8ghz,24 inch 3.06ghz or the 20 inch 2.66ghz?).Also, where can i learn Cocoa,X code? How long does it take to develop a app?(for example a calendar app,alarm app?)