It says "In stock soon. Order now to get in line. First come, first served." again at Amazon. My guess is that Amazon's supply is just like every other store's right now: they don't know when they'll get any in, and they sell out extremely fast when they do get some.
Late last week I decided I wanted to get my wife a 1 GB shuffle for Valentine's day. I knew I'd waited way too long and I might not be able to get one in time. One nice thing about living in southern California is that there are 9 Apple Stores within an hour's drive, and 2 more down in San Diego. I started calling them one by one on Monday afternoon.
The first couple stores said they had none in stock and didn't know when they might get any more. They also said they weren't doing a waiting list because supply was so scarce. Then one store had some 512s but no 1 gigs. I was tempted to jump on that, but kept calling. Finally one store had both in stock and was willing to hold a gig shuffle for me for only 2 hours. I jumped in the car and fought traffic to get down there, and just barely made it (I don't know how strict they would have been on the 2 hours thing, but none were on the shelves in the store).
So just like everyone else, the Apple Stores are also getting just sporadic supplies and selling out very quickly. I still feel pretty lucky that I got one in time for V-day. 😀