PostgreSQL 8.4 - permissions for newly created tables?

Hi All.

I have to setup a new infrastructure with postgre software. I would like to
use user access patterns from mysql if possible. For every application:
1) one user for reads: grant select on db.* to 'reader'@'ip space' ...;
2) one user for reads/writes: grant update,insert,select,delete on db.* to
'writer'@'ip space' ...;
3) every user comes from a defined IP address space.
I would like to give one postgre db to one application.
1) and 2) - Is it really necessary to give permissions for newly created
tables for such users every time a table is created (I am using 8.4, not
9.X)?
3) I think that kind of functionality is best to accomplish with
pg_hba.conf?
I also would like to give ALL database for newly created application
database rights for a lead programmer, so then he/she could give
permissions for newly created objects to reader/writer application roles.

Is it the best way? Any hints?

Best regards,
Rafal Radecki.