If you want to know where Azure datacenters are located in the world take a look at this page:
If you want to know which services are available in those centres take a look at:
If you do a lot of Office 365 demos like I do, it makes sense to build a clean virtual workstation in a datacenter that is near the Office 365 datacenters. For me that is in Singapore which equates to Southeast Asia when running up an Azure virtual machine. That way you get the best experience possible between Office 365 and workstation, which is why this configuration is great for demos (apart from the fact that you can run them anywhere and on any machine that has Internet connectivity).
I’m sure there’ll be more regions soon, so stay tuned to those pages for all the details.