Well, maybe it's not quite that dramatic - but Apple has announced that they will be using Intel based CPU chips in the future - by June, 2006 and fully switched over by 2007. Nothing really that earth shattering to the average user, or even most power users. Apple has been running a version of OS X on Intel CPUs for 5 years now so it's not a recent idea. Obviously some code will have to be rewritten/recompiled but the whole keynote today was run on a Intel based Mac so obviously they're pretty ready for this. They also switched platforms once before when OS 9 came out so it's something they've done in the past.
The main reason for the switch is simply that IBM hasn't been able to deliver on processors in both speed (GHz/Mhz) and quantity as well as putting their G5 chips in laptops. It'll be interesting to see how performance is using Intel based CPUs and how it will affect the whole Mac vs. PC argument now that they're running on the same platform.
