na G4 sa mozes naucit programovat v Objective-C a Cocoa ale bohuzial nie pre iPhone – len pre OSX.
Kazdopadne je to vynikajuci zaklad pretoze ak budes vediet Cocoa (pre OSX) tak viacmenej automaticky budes vediet aj Cocoa Touch.
EDIT: copy+paste z readme aktualnej verzie xcode
Compatibility: Xcode 3.2 requires an Intel-based Mac running Mac OS X Snow Leopard version 10.6.2 or later.