About unsigned smallint?

Greetings,

Can I know whether postgreSQL 8.0 supports unsigned smallint please? I
looked at the doc, it seems that OID is unsigned interger. While I was
trying to create a simple table as:
      create table test (id unsigned smallint);
                             or
      create table test (id smallint unsigned);

It seems that postgreSQL did not support unsigned integer?

Thanks a lot,
Emi