Apache Guacamole is a clientless remote desktop gateway. It supports standard protocols like VNC, RDP, and SSH.
We call it clientless because no plugins or client software are required.
Thanks to HTML5, once Guacamole is installed on a server, all you need to access your desktops is a web browser.
Remote Desktop (RDP) Server/Client for Windows Vista or higher
Remote Desktop (RDP) Server/Client for Windows Vista or higher (any edition). Uses Windows Desktop Sharing API. Supports multiple concurrent users with view only mode (screen broadcasting).
properJavaRDP is an open source Java RDP client for Windows Terminal Server. It is based on rdesktop, a SourceForge project. properJavaRDP runs on Java 1.1 up (optimised for 1.4), and works on Linux, Windows and Mac. It also includes log4j-java1.1.