I've created a virtual PC and installed Server 2003 R2 on it. I have added the application server role. I can get to the default site using http://localhost on the VPC. The VPC can access the internet.
I can't however ping the VPC from my physical desktop (host machine). I've tried adding a second network adaptor in the VPC console and giving this a static IP but to no avail.
It depends on how you have networking setup. I you have it setup with NAT, then Virtual PC is assigning a private IP to the VPC (likely on a different subnet than your host PC). If you have it setup to use the same network adapter as your host OS is using, then (if I recall correctly) it should get another IP from your router, and you can try pinging it via that IP, although (if I recall) that is tricky in that it has two IP addresses using the same MAC address, and your NIC would not know where to route packets. If you have a second network card in the host, you could assign it to the Virtual machine and try connecting to it that way.
Could you perhaps post information on what the TCP/IP settings are for the host and guest, as well as information on the type of networking you have setup in Virtual PC?
It looks like you've set it up NAT'd behind the host. So nothing can access it. You need to bridge it to the network adapter. Then you'll be able to access it from any machine on the network.