Sony reportedly bumped into production problems, and will only have 200,000 units ready for the Japanese launch, with 500,000 ready by "the end of the year" (which might be either December 31 or March 31). And that's just Japan. Other regions don't even have an officially confirmed launch date or price yet.
Nintendo's got 570,000 on launch day, even more by Dec 31, and is supposed to have 1,000,000 (and that's an old number) by March 31 in Japan. Plus they've already got their American launch.