The usual online stores for me are:
I've had good luck with each of them and tend not to shop elsewhere (aside from apple.com) if I can help it.
- NCIX: sold out (it's never been 'in stock' so far as I've noticed)
- tiger direct: doesn't list it
- Newegg: sold out (never been in stock)
- Memory Express: not listed
Amazon is listing it as out of stock now too. There are comments/reviews but when you read them, they're people who have the 250gb version. (It's also listed at $720, my order was $670/ea). That sort of thing makes me nervous because the exact same nonsense happened with the Crucial disks. Your ship date comes, they push it back a week…then another…