Arstechnica notes that the AppleTV will also be found at some Costco stores for $289.
In other news, a reader and friend of mine Dan Ciskey e-mailed me over the weekend, saying that some Costcos may also be carrying the Apple TV. He said that the one he works at in Lincoln Park in Chicago has them (apparently without fanfare) for $289.99 and that they don't charge a restocking fee upon returns. He says, "I believe the old, unlimited return policy would apply. The new 90-day thing is actually limited to a few categories of items," which he doesn't believe includes the Apple TV.