[R-SIG-Mac] Help with R install on OSX 10.4.7

[Heather Coiner]

I downloaded the R-2.4.0.dmg, and was confronted with 4 packages,  
gcc403.pkg, R-GUI.pkg, R-Framework.pkg, and tcltk.pkg, along with a  
warning to use R.mpkg to install, which I didn't see anywhere.  What  
are these 4 packages, and which do I need for a basic install?  I am  
a UNIX and R newbie, but interested in learning.

Thanks!
Heather