Sun Documentation : Online Documentation from Sun Microsystems 
Sun FreeWare : FreeWare for Solaris 

ZD Net Webopaedia: ZD Net's Search Site for Technical Info 
Net Lingo : The Internet Language Dictionary 
Dictionary of PC Hardware and DataCom : O'Reilly's online dictionary of PC Hardware and DataComm Terms 

Lockergnome : For Widows/Linux Users 

NetCraft WebServer Survey : Query a Web Site to find what Server it is using ! 
 

Oracle Sites: Official and Unofficial Oracle Sites