Vendetta Studio has Omniball (iTunes Link) in the iTunes App Store for FREE for a limited time.

Omniball is a casual arcade/sports game designed exclusively for the iPhone and iPod touch. Omniball expands the 2D multiplayer ping-pong genre in all directions. Choose a color and score points by spinning your paddle around a circular arena using the simple and intuitive sliders to deflect the color-changing ball back at your opponents.