…ist überhaupt kein Problem, dank PEAR.
Nachdem Frank heute mit Windows schon etwas herumgeflucht hat - hier nochmal die Ubuntu-Style-Variante:

bascht@baschtmobil:~$ sudo pear channel-discover pear.symfony-project.com
Adding Channel "pear.symfony-project.com" succeeded
Discovery of channel "pear.symfony-project.com" succeeded
bascht@baschtmobil:~$ sudo pear install symfony/symfony
downloading symfony-1.0.2.tgz ...
Starting to download symfony-1.0.2.tgz (1,903,264 bytes)
.................................................................................done: 1,903,264 bytes
install ok: channel://pear.symfony-project.com/symfony-1.0.2