The Retina Difference is a free App which demonstrates the sharpness of the new iPhone 4 / iPod touch Retina display by showing the difference of optimized vs. unoptimized grahics on the iPhone 4 /...
AudioPairs Free Edition - a sound matching card game for the iPad, iPhone 3G, 3GS, 4 (optimized) and iPod Touch 2nd/3rd generation with full iOS4-support like fast app switching!