# shell command:
pg_dump <db_name> -U <db_user> -h <db_host> | gzip | curl -u <ftp_user>:<ftp_password> ftp://<ftp_host>/`date '+%Y-%m-%d_%H-%M'`/db_backup.sql.gz --ftp-create-dirs -T -

# if you want to execute it through cron, be sure to escape all %!
# for crontab:
pg_dump <db_name> -U <db_user> -h <db_host> | gzip | curl -u <ftp_user>:<ftp_password> ftp://<ftp_host>/`date '+\%Y-\%m-\%d_\%H-\%M'`/db_backup.sql.gz --ftp-create-dirs -T -