grant select on all tables

Hi,

I need to have default privileges like "GRANT SELECT ON
ALL TABLES" for a particular user. Looking at the docs &
mailing list archives there's no easy way to do this. I
seem to have to run a grant statement every time a new
table is created, so I thought of running the grant
automatically as a trigger on the pg_tables table.

I got as far as creating a function to help me do the
grant part:

create or replace function grantAccess(text, text)
returns text as '
DECLARE grantStmt text;
BEGIN
grantStmt := \'grant select on \'||$1||\' to \'||$2;
EXECUTE grantStmt;
RETURN grantStmt;
END;'
language plpgsql returns null on null input;

I wanted to run the function in a trigger on the
pg_tables table, but I can't cos it's a view. So I tried
setting it on the pg_class table, but I can't do this as
it's a system catalog.

Can anyone help?
Can anyone see a better/easier way of doing it?

Cheers

Andrew