I was playing around with creating a virtual lab for a Microsoft Certification I had to do, using Hyper-V on Windows Server 2008 R2. This involved setting up several VMs, which would need updates etc.
Since my desktop computer uses a wireless USB card for internet connection (my home router is quite a ways away for an ethernet cable and I am too lazy to route one through the wall :) ), I had to figure out how to do this.
First step, of course, is to make sure that the Hyper-V host can actually utilize the USB wireless dongle. Apart from drivers, you will need to install the "Wireless LAN Service" feature (or you might get stuck for a couple of days trying to figure out why the dongle doesn't work when it should - like I did :) ).
Next you will need to do a couple of things; Ken Schaefer's blog post was the starting point. Though mostly text based, he links to a blog post by John Paul Cook which provides an illustrated version of Ken's post (as well as an alternative method). Basically, you leverage the Windows Server RRAS role, namely NAT, to route traffic from your Hyper-V Internal network (it needs to be internal - external binds the network to a physical NIC, whereas private does not allow access to the host machine) to the Wireless interface.
What the above blogs failed to mention was a small but important detail: when assigning an IP address to the internal network interface, that address needs to be in the range of the IP addresses used by the VMs. So, if your Hyper-V internal network uses a 10.0.0.0 network, you should allocate an IP within that range (as an example, 10.0.0.250).
Once that is done (assuming the VMs are server OSs and are assigned a static IP address), you need to make sure you can both communicate with the Internet and with any Domain Controllers you may have as a VM (at least, in my case - remember, this is my lab setup). So, the final step is re-configuring the NICs in the VMs to have as a Gateway the IP you assigned to the Internal network NIC (i.e.10.0.0.250) and the DNS servers should be your Domain Controller's IP as primary, and the Internal network's IP address.
The above allowed me to access the internet from the Hyper-V VMs, and do what was needed. Cheers :)