Samba is available via anonymous ftp from nimbus.anu.edu.au in /pub/tridge/samba/.
If you don't have anonymous ftp access then use
ftpmail
(http://www.cuhk.hk/guides/earn/ftpmail.html) and
get the file samba-latest.tar.gz. The current version is 1.7.07, but
that will probably be out of date by the time this is printed.
Samba will probably appear in upcoming versions of the Slackware
and Debian distributions. It's also likely that you'll find it on the
major Linux archive sites such as
tsx-11 and sunsite.