Default postgresql encoding is determined when initdb is run, which currently takes place in /etc/init.d/postgresql service script. As this choice has some important consequences on subsequent server functionning, i'm not very happy having it running behind the scene without any way to configure it.
Moreover, it default to SQL_ASCII, which seems to have broken UTF8 conversion, whereas LATIN1 would be more natural on Linux platform. Switching to LATIN1 as default (aka adding -E LATIN1 to initdc command in service script) would be a lesser evil IMHO. -- Disks are always full. It is futile to try to get more disk space. Data expands to fill any void. -- Murphy's Computer Laws n°4