Get IP Address in Virtual Network

Hi. 

When associating a cloud service with a specific virtual network, the instance automatically gets an IP from the selected subnet range. 

Is there a way to know this IP dynamically from within the instance itself? If so, is this information available as soon as the instance is created, for instance at the time when startup tasks are executed?

If not, is there a way to get this IP at any time after the instance is created, from outside the instance, programmatically?

I prefer a PowerShell solution, but anything would do. 

Thanks.