UPDATE 12:09 PM: I didn't make it clear in the original article the update will be compatible with the most recent iPod Touch (aka 3rd gen). It will not work on previous iterations of the hardware, same as iPhone.
ORIGINAL STORY: iPhone, iPhone 3G, iPod Touch and iPod Touch 2nd Gen users, there's some bad news. According to Apple, the hardware isn't powerful enough: you aren't getting multitasking.
Apple sneaked this particularly important tidbit into the last minutes of their presentation this morning at the Apple campuses in Cupertino, California. Get ready to begin groaning loudly.
“For iPhone 3G and iPod touch 2nd gen, they will run many things, but not everything," said Jobs, before the bombshell. "They will not support multitasking, the hardware just can’t do it.”
iPad will also be receiving the iPhone OS 4.0 update, but it won't happen until sometime in the fall. Apple did not reveal a reason iPad users would have to wait several extra months for it.
iPhone OS 4.0 is scheduled to launch this summer. An updated iPhone to be sold later this year has been heavily rumored, but Apple made no mention of a new iPhone at any point today.