I have Ubuntu as the main OS. I installed VirtualBox with a Windows XP guest. How can I share files between the two OSs, and how do I connect to the Internet in the Windows XP guest?
Stop your virtual machine. Go to settings (in Virtualbox -> XP guest -> settings) and search for shared folder. Add a folder on your PC like /home/username/Documents/vmshare . And there you go.
Note: You have to install Guest Additions to the guest for this which you can get from Tools-> Guest additions (when your guest is running. It'll mount the VBox iso and install the additions. All you need is a reboot after that.)
For shared folders;
XP will get an IP from your router and act like an independent machine on your network.