A Query on PG_ tables

Hi everybody,

    I'm using Postgresql 7.0.

    I want to find, by a query on the postgres table (like pg_class,
pg_attribute, pg_trigger, etc....), the name of all the colonnes  that
are foreign key on my base.

Pg_trigger gives me some information about the foreigns key i added on
my tables (name, id etc..) but i don't know how to join this information
with another pg_<table> (for example, pg_attribute or else) to find the
name of my colonnes that are foreign key.

Someone have an idear ?

I hope i was clear with my poor English...

Thanks for your answers.

Nicolas.