installing gcc v4 on AMD64

[kenneth kahn <kenkahn@xxxxxxxxxxxxx>]

I want to install gcc v4 on a RHEL v3 system (amd64).  I see the files on

 ftp.gnu.org, but I'm not sure which ones I need;

     gcc-4.0.0.0
     gcc-core.4.0.0.0
     gcc-g++.4.0.0.0
     gcc-testsuite.4.0.0.0

 What's the difference between gcc and gcc-g++; what is gcc-core and
 gcc-testsuite?  I want to install the basic gcc/g++ compilers along with
 their support libraries.

 Thanks...