replacement for LEFT JOIN in mysql->postres changeover?

Hi all,

I am trying to figure out how much work is involved in migrating an
existing mysql database and web/command-line perl interface to postgres.
I got some scripts hacked together that can translate the mysql schema and
data dump ok, but I ran into a

ERROR: parser: parse error at or near "left"
ERROR: OUTER JOIN is not yet supported

message when I tried some of the interface scripts. What is the
recommended way of handling this; and does anyone know of other big
gotchas in coming from mysql?

thanks,
-emile