With x2go you can access your desktop using another computer -- that means both LAN and internet connections. The transmission is done using the ssh protocol, so it is encrypted. By using the free nx libraries from NoMachine, a very acceptable performance in both speed and responsiveness is achieved. Even an ISDN connection runs smoothly.
This makes it is possible to connect your laptop to any computer with the environment, applications, and performance of the remote desktop. It is also possible to have a bunch of computers connected to a single server (terminal-server, thin-client).
Clients are available for Linux (Qt4), Windows, and Mac. The latter two can be downloaded directly as binary from the x2go homepage.