Best way to import data in postgresl (not "COPY")

Hello,

I have a system that must each day import lots of data from another one.
Our system is in postgresql and we connect to the other via ODBC.

Currently we do something like :

SELECT ... FROM ODBC source
foreach row {
INSERT INTO postgresql
}

The problem is that this method is very slow...

Does someone has a better suggestion ?

Thanks a lot in advance !

Denis