Every Windows Vista computer is part of either a workgroup or a domain. You can share resources with other computers through either of these networks. You can change your network configuration and switch between workgroup and domain connections.
If your domain supports VPN connections, you can connect your computer to a domain over the Internet, from any location.
You can connect to a domain computer from another computer and work on it as though you were sitting in front of it, by using Remote Desktop.
You can connect over the Internet to a remote computer and interact with it directly as though it were your own desktop.