VNC Server connection using RDP

1) Can someone tell me if VNC server was included in the Redhat distribution 5.9 or 5.6

2) I am try to remove sunray server from my system and replace it with VNC server. (RH 5.9 with Sunray Software)

3) I am also trying to find out how many connections can I have using VNC server... do I need a VNC server process for every connection ?

Any help with this is appreciated

Thanks Kelly
kelly_lee@raytheon.com