windows 7 - How to make Ubuntu VM in VirtualBox accessible from the internet?

I'm trying to set up an Ubuntu server in VirtualBox.

The host is Windows 7 x64.

The guest is Ubuntu 11.10 x64.

I want to make this server accessible from the internet. How can I do it?

Answer

This is largely depending on how you set the networking for your VM. If you have set it to NAT, you will have to configure port forwarding in VirtualBox.
If you have set it to Bridged, you will have to set up routing between the VirtualBox networking adapter and your physical network adapter. But that shouldn't be a VirtualBox-specific issue.