BUG #2468: how to create auto-generate primary key

The following bug has been logged online:

Bug reference:      2468
Logged by:          vivekananda
Email address:      r.vivekanandaswamy@rediffmail.com
PostgreSQL version: 8.1
Operating system:   Windows-2000
Description:        how to create auto-generate primary key
Details:

Hi,
Good morning all.How to create automatic generated key while creating table
like OID's.is there any posibility to create this one?

for example create table emp(no numaric(3),name varchar(10))

here there is no primary key explicitly.But i want use primary key with
adding 3rd column for generating querys.

OID's are uniqe for all tables.but i want impliment this feature only for
specified table.How?