It seems that EA and SEGA both think that the iPhone SDK is up to the job:
"The animation technology in the iPhone OS enables us to build awesome games,” said EA chief executive John Riccitiello. "I think iPhone consumers are going to be blown away by the games we create for this platform."
Similarly, SEGA's Ethan Einhorn showed off a version of his firm's Super Monkey Ball title that leveraged the iPhone's Accelerometer, and like Spore was also ported to the handset within two weeks. To move the monkey around the screen, all players have to do is tilt the iPhone.