Citrix is the cross-platform competitor to Microsoft's Terminal Services. Its ICA protocol (TCP over port 1494) is allegedly lighter and more performant than RDP, but if you ask me, it isn't that hot in terms of user experience.
You see, a standard install is usually crawling with IE-specific junk to allegedly make it easier to launch applications, and you're usually better off using the ICA connection manager and configuring connections by hand - and not using the browser at all.
Resources:
- GlobalSign SSL Root Certificate (needed for our particular config and some non-Windows clients)
- Brian Madden's Book, available as a PDF.
- Citrix Yahoo widget
- Bruno's notes on running it on older Ubuntu versions.
Notes:
- The Mac OS X client (version 7.0) only installs properly under an administrative account - in the sense that it doesn't even know how to ask for the administrative password and bombs out. It has no provision for a system tray/notification area or support for seamless windows.
- The Java client supports seamless windows in Mac OS X, but it requires some tweaking and careful reading of the documentation (it is also buggy, but tolerably so).