From TightVNC Software:
TightVNC for Linux is a remote control package derived from VNC, with many new features, improvements, and bug fixes over the standard VNC version. It works well with slow network links such as modem connections, provides more configuration options in the server, includes improved Java viewer, and more. The modified servers and viewers are fully compatible with the original VNC software.
What's new in this version:
Version 2.6.4 has fixed a number of minor problems discovered in version 2.6 and updated built-in Java Viewer.