Please see http://www.samba.org/ for a list of mirrors and
always use your closest mirror. 

You only need to download 1 file to get a complete copy of Samba. Look
for the file samba-latest.tar.gz. This is a soft link to the latest
version. You will need gunzip and tar to unpack the archive. 

This file includes all the documentation as well.

Should you prefer to download ready to run files there may be a binary 
installable kit for your system under the pub/samba/Binary_Packages directory
tree. These have been contributed by other users and are made available as a
service to the samba user community but without any endorsements.