Q-SeeMe works well for Cuseemee connections but the last uild only supports black and white video. http://www.pangea.org/~mavilar/qseeme/qseeme.html
The openh323.org project has an application named OpenPhone which works pretty well for video conferencing but doesn't offer the whiteboard, file sharing etc. of Netmeeting. http://www.openh323.org/
C30 was really good but the project has been converted to a commercial solution named Qvix. You can still find the version 1.0 of C30 at http://cu30.sourceforge.net/,
and information on the Qvix app at http://www.qvix.biz/index.php.
But, what is wrong with Gnomeeting?