This may turn out to be a mistake on Amazon's part, but right now Google Chromecast is listed as being for sale, right now, and Prime-eligible. That means you can have the crazy new must-buy streaming dongle shipped to you by the end of the week for free if you're a Prime member, or by end of day tomorrow for an extra eight bucks. Crazy.
Remember, too, that Chromecast includes three free months of Netflix (whether you're a new or existing member), so the $35 dongle really costs you $11.
By contrast, if you had bought Chromecast this morning from Google's Play Store, the earliest shipment you could have gotten was August 2nd, and the current wait is until August 7th. Play Store purchases are also tagged with tax and (slower) shipping rates. So, uh... hope you waited! [Amazon]
Update: Amazon's now saying it could be an extra 1-2 days before shipment. That still puts you well ahead of the Google Play timeline, but you should act quick!
Update 2: Annnnddddd now we're at 3-4 weeks. That was fun while it lasted!