Postgres 8.0 -> BEGIN EXCEPTION END Syntax????

Hi ,

can anybody tell me the postgres - syntax for begin excepion end if I
want to ignore the error?

BEGIN
  exception ...
EXCEPTION
  WHEN OTHERS THEN ?????????????what to write for do nothing?????????
END;

in oracle it's

WHEN OTHERS THEN null; but this syntax doesn't work in postgres.

thnx

Daniel