We saw an early demo of Sega's Super Monkey Ball back at the iPhone SDK event in March, but it looks like the real thing is ready for WWDC, with some 110 stages and all four classic monkeys, including Baby. We just caught a quick run-through during the keynote, but the graphics look unbelievable compared to anything we've seen on a cellphone before -- easily DS-quality graphics.
Also demoing games was Pangea, whose Brian Greenstone showed off Enigmo and Cro-Mag Rally, a racing game that uses the iPhone itself as the steering wheel, via the accelerometer. Again, the graphics were high-quality, and gameplay was described as "totally playable" with just a minimum of porting effort -- three days for each game.
Finally, Digital Legends Entertainment demoed a God of War-type game that they had developed in only two weeks that featured graphics somewhere between the DS and PSP. It'll be ready sometime in September.
Pricing for all three games was set at $9.99 to start -- high for a cellphone game, sure, but super competitive with other portables.