Framework for building 2d games for Iphone, Ipad and Ipod Touch

cocos2d for iPhone is a framework for building 2D games, demos, and other graphical/interactive applications. It is based on the cocos2d design: it uses the same API, but instead of using python it uses objective-c.

Main features

• Scene management (workflow)
• Transitions between scenes
• Sprites and Sprite Sheets
• Effects: Lens, Ripple, Waves, Liquid, Twirl, etc.
• Actions (behaviors):
• Trasformation Actions: Move, Rotate, Scale, Jump, etc.
• Composable actions: Sequence, Spawn, Repeat, Reverse
• Ease Actions: Exp, Sin, Cubic, etc.
• Misc actions: CallFunc, OrbitCamera
• Basic menus and buttons
• Integrated Box2d and Chipmunk physics engine
• Particle system
• Text rendering support
• Texture Atlas support
• Tile Map support
• Parallax scrolling support
• Streak Motion support
• High Score server (Cocos Live)
• Touch/Accelerometer support
• Sound support
• Portrait and Landscape mode
• Integrated Pause/Resume
• Supports PowerVR Texture Compression (PVRTC) format
• Language: objective-c
• Open Source: Compatible with open and closed source projects
• OpenGL ES 1.1 based

For more details refer http://code.google.com/p/cocos2d-iphone/