can anyone Explane
How to upgrade from RC x to VB3.0.0 gold?

Oh that's easy!
1)Backup your DB and RCx PHP files
2)Upload the new vB3 Gold files, overwriting the old ones in the process
3)Run www.yoursite.com/install/upgrade.php
4)Go through the wizard
5)Go to AdminCP -> Styles & Templates -> Find Updated templates. Here you will have to edit your customized templates to reflect the changes made in the new versions of the templates (it is not required if they are just design issues).

thank you so much for your help and time

RN_Evil (http://www.vBulletin-Fans.com/member.php?u=6) vbmenu_register("postmenu_31194", true);

No problem. The manual on vb.com covers it in more detail though, so read it too :)

http://www.vBulletin.com/docs/ is the link i believe.