I case you didn't see this over at xda...
Google Help Update
We’ve had incredible demand for our new Nexus 7 tablet and are shipping them as quickly as possible. When your device ships you will receive a notification from Google Play with a shipping tracking number. We will have all orders processed and shipped soon - thanks for your patience.
Below are more specific details by country. If the below information is not true for you, please reach out to our support team so we can investigate.
In the US: We’ve shipped all standalone Nexus 7 8GB orders (e.g., those without a case, charger or Nexus Q). By the end of day on July 19 (PDT), we will have shipped all standalone Nexus 7 16GB orders placed through July 11 (PDT), and upgraded these orders to overnight shipping. We will process the remaining standalone Nexus 7 16GB orders by the end of next week with overnight shipping.
If you ordered your tablet with a case, charger or Nexus Q, your Nexus 7 will ship this week with overnight shipping, in some cases ahead of the rest of your order. Don't worry - the rest of your order will be on its way shortly.
In Canada: We’ve shipped all Nexus 7 8GB orders. We are in the process of shipping Nexus 7 16GB orders and will ship them in 1-2 weeks.
In the UK: All Nexus 7 8GB orders will ship by July 20 (BST). All Nexus 7 16GB orders placed through June 30 (BST), will ship by July 20 (BST). The remaining Nexus 7 16GB orders will ship next week.
In Australia: All Nexus 7 8GB and Nexus 7 16GB orders will be fulfilled by the end of day on July 19 (AEST) and will arrive in 3-5 days.
http://support.google.com/googleplay/bin/answer.py?hl=en-GB&answer=2667319&ctx=plusone