General Information

RDP stands for Remote Desktop Protocol, it is Microsoft's proprietary protocol for remote desktops.
Click here to see how it compares to the other protocols.
There are open-source implementations available. The server generally runs on port 3389.

Microsoft Windows Limitations

Although the "client" software (for connecting to other computers) is included in all versions of Microsoft Windows since XP, the server component is not available in all versions.
It is not included in XP Home, and quite a few versions of Vista and 7 including, 7 Starter, 7 Home Basic, or Windows 7 Home Premium.

Features

Window Switch can only use RDP to connect to a Microsoft Windows machine and forward the desktop to the client's display.
Although there are other features and other servers, these are not supported at present.

(Mostly due to unnecessary licensing restrictions which have nothing to do with the technology)

Links

• rdesktop.org: an open source RDP client.
• freerdp.com: another open source RDP client (forked from rdesktop).
• Xrdp: an open source RDP server. (not supported)
• RDP on Wikipedia has much more information and links