With the Google Nexus 7 getting rave reviews, just about the only mystery still surrounding the device is how you can buy one — constrained supply has led to confusion over exactly when orders from the Play Store will arrive. In an attempt to clear all this up, Google has taken to the Play Store itself to update customers on their pre-order status. It appears that going for the 16GB model or ordering accessories at the same time may have delayed your delivery — all standalone 8GB orders in the US have shipped, but 16GB orders placed before July 11 will be shipped by July 19, with later 16GB orders to be completed by the end of next week. It's possible, too, that your Nexus 7 will arrive ahead of accessories such as the case, charger, or Nexus Q.
In the UK, your Nexus 7 will have shipped by July 20 as long as you ordered it before June 30, but customers who ordered the 16GB model after that date will have to wait until next week. All Australian orders will be shipped by July 19, and while all 8GB orders have shipped in Canada there'll be a 1-2 week wait for the 16GB model. Google is also allowing for the possibility that these times won't hold true for everyone, and urges those affected to contact the support team. Of course, those making new orders today will still have quite some time to wait regardless, but at least it looks like the earliest adopters should be dealt with soon enough.
Update: As spotted by Talk Android, the 8GB Nexus 7 is now listed as "in stock" on Google Play and should be shipped to you straight away.