Remote Desktop tools for Linux

rdesktop is a very good tool to connect to windows servers remotly. Kind like Citrix but wihtout the need for server extensions.

grdesktop is the frontend for rdesktop. It features saving the connections and browsing the network for terminal servers.

But the truly amazing tool is tsclient because not only it supports windows terminal server protocol, BUT also supports XDMCP (via Xnest) and VNC protocols.