You can now view failed login attempts in dba_audit_trail:
select
os_username,
username,
terminal,
to_char(timestamp,'MM-DD-YYYY HH24:MI:SS')
from
dba_audit_trail;
OS_USERNAME USERNAME TERMINAL TO_CHAR(TIMESTAMP,'
--------------- --------------- --------------- -------------------
fred SCOTT app93 05-16-2009 16:21:13