NaturalMotion has Jenga (iTunes Link) for the iPhone and iPod Touch and Jemga HD for iPad in the iTunes App Store for FREE (regularly $2.99) for a limited time.

The official Jenga game is here! Designed in consultation with Leslie Scott, the original creator of Jenga, Jenga for iPhone/iPod touch/iPad lets you take the tower building experience anywhere. Now with online multiplayer.