You can get DBMail either pre-packaged or compile it yourself from source. This page describes the different methods.
* Debian
There are DBMail Debian packages available. DBMail 2.0.x is in the stable and 2.1.x in the unstable tree. The Debian packages are being maintained by Paul J Stevens.
Depending on which version you need you add the following line to /etc/apt/sources.list:
"deb http://debian.nfgd.net/debian stable main" "deb-src http://debian.nfgd.net/debian stable main"
To get DBMail version 2.1.x on debian stable follow the directions here
* Red Hat Enterprise Linux
There are RHEL rpm packages avaliable. At this moment assembled initial release of 2.2.1 and support libraries. Dbmail 2.2.1 requires gmime >= 2.1.19, libsieve >= 2.1, glib2 >= 2.10. Postgresql section of dbmail spec file wasn't tested.
Packages maintained by Alexey Marushchenko.
Site is russian-only, but here are direct links
dbmail packages - http://marush.com/2007/02/06/dbmail-222-1/
gmime packages (without mono support) - http://marush.com/2006/12/04/paketyi-dlya-dbmail-chast-1-gmime/
libsieve packages - http://marush.com/2006/12/04/paketyi-dlya-dbmail-chast-2-libsieve/
glib2 packages - http://marush.com/2006/12/04/paketyi-dlya-dbmail-chast-3-glib2/
1) Get the sources
Download a source from http://www.dbmail.org/index.php?page=download
2) Run configure & make
Run the configure script. This script uses pg_config or mysql_config (depending on --with-mysql or --with-pgsql) to detect where the libraries and include files for these databases are. e.g. when working with PostgreSQL, this is the configure command: ./configure --with-pgsql After running configure, 'make all' will build the executables. Running 'make install' will install the executables in /usr/local/sbin