Fling
Ten One Design have announced Fling which is a tactile game controller for iPad. Fling gives you a physical control facility using an attachable analog joystick. It can be used to control any game that has a virtual joystick! You can pre-order now for about 25 USD.
Stop worrying about the controls and take your skills to the next level.
Miss your console? Fling gives you the feel of an analog joystick, so your iPad games feel even more immersive.When the screen illuminates, Fling melts away and becomes invisible, so you’ll never miss any action on the screen.
I think Fling is the best for iPad game controller.