It looks like the cat and mouse game continues. According to MuscleNerd and the iPhone Dev Crew, a new BootROM called iBoot-359.3.2, is appearing in new iPhone 3GS units that is resistant to the 24kpwn exploit used by the Dev-Team and others to jailbreak the iPhone. At this point, and in the immediate future, there doesn’t look to be a jailbreak for this ROM.
But, you know how this works. Give it a month or so and we’ll probably be back to jailbreaking again. In the meantime, refurbished iPhone 3GSes are going to be the hot item.