Happiness is a cross database link...

I am trying to find out some information on how to set up a cross
database links so that I can have queries and foreign keys that cross
a physical database.  This is not just a technical requirement, but a
legal one (The client requires that we do not co-mingle data).  I have
a new database that has tables and indices named using a new naming
schema, and an old database that was implemented based on a customer
requirement that is ugly, and I don't really want to put everything
into one database (technical reason).  I have read that contrib/dblink
can do this, but I am unable to find any documentation for this
features, or infact any documentation on what is in the 'contrib'
pacakge.  Can anyone point me to a good place to find contrib docs, or
and point me to database cross linking stuff.  My boss will be really
pissed if I tell him we need to spend $10k to implement Oracle to have
a good solution ;)

Thanks,

Alex Turner
NetEconomist