I did a Server install of CentOS 4.4 and made sure that Postgresql was enabled as well as php-pgsql and other reasonable things were selected. Then proceeded to get MySource Matrix installed. It went on fairly easily. Here's everything I did taken from my history file. I think it should be pretty complete, but I edited out my missteps for clarity. Also some of the steps might not be necessary (php-gd and php-mysql for instance), but I left them in because I did them.
I downloaded the mysource_3-10-4.tar.gz file first. Then proceeded with the following
commands:
mv mysource_3-10-4.tar.gz /var/www
cd /var/www
tar zxvf mysource_3-10-4.tar.gz
Then dowloaded the php_cli file from the sticky thread on the top of this
forum and proceeded with the following commands:
rpm -Uvh php_cli_4.3.9_3.sqz.i386.rpm
yum install php-gd
yum install php-mbstring
yum install php-mysql
pear install Mail_Mime
pear install XML_HTMLSax
/etc/init.d/postgresql start
su - postgres
createuser matrix
createuser matrix_secondary
createdb -O matrix -E SQL_ASCII mysource_matrix
createlang plpgsql mysource_matrix
cd /var/www/mysource_matrix/
php-cli install/step_01.php /var/www/mysource_matrix
rm /var/www/mysource_3-10-4.tar.gz
Then edit the main.inc file to the values recommended in the database install
instructions:
vi data/private/conf/main.inc
Then edit pg_hba.conf to change "ident sameuser" to "trust":
vi /var/lib/pgsql/data/pg_hba.conf
The proceed on with the following commands:
/etc/init.d/postgresql restart
php-cli install/step_02.php /var/www/mysource_matrix
php-cli install/compile_locale.php /var/www/mysource_matrix
php-cli install/step_03.php /var/www/mysource_matrix
php-cli install/compile_locale.php /var/www/mysource_matrix
chmod -R 755 /var/www/mysource_matrix
chown -R apache:apache data cache
chmod -R g+w data cache
vi /etc/httpd/conf/httpd.conf
/etc/init.d/httpd start
crontab -u apache -e
Then download the java plugin from Sun and install it so you can use the interface:
chmod 755 jre-1_5_0_09-linux-i586-rpm.bin
./jre-1_5_0_09-linux-i586-rpm.bin
cd /usr/lib/mozilla/plugins/
ln -s /usr/java/jre1.5.0_09/plugin/i386/ns7/libjavaplugin_oji.so .
And it all seems to be working fine. I can log in to the admin interface and changed my password.
Now to figure out what to do with it…
Heh. I would recommend upgrading from the stock PostgreSQL that ships with CentOS 4.4 to PostgreSQL 8.1 - you'll get a significant performance increase. 
Otherwise, this is great!