MacOS X comes with a VNC server, but it has problems: you can’t access it depending on what client version you’re using, and it seems to work only on full-quality mode (32bit color?), so it’s slow like hell.

An alternative is installing the marvelous Vine Server,which on its 3.0 release brings full client/server clipboard integration and works like a charm with any Linux VNC client, fast and without problems.