How do I get the current year using SQL on Oracle?

Using to_char:

select to_char(sysdate, 'YYYY') from dual;

In your example you can use something like:

BETWEEN trunc(sysdate, 'YEAR') 
    AND add_months(trunc(sysdate, 'YEAR'), 12)-1/24/60/60;

The comparison values are exactly what you request:

select trunc(sysdate, 'YEAR') begin_year
     , add_months(trunc(sysdate, 'YEAR'), 12)-1/24/60/60 last_second_year
from dual;

BEGIN_YEAR  LAST_SECOND_YEAR
----------- ----------------
01/01/2009  31/12/2009

Another option is:

SELECT *
  FROM TABLE
 WHERE EXTRACT( YEAR FROM date_field) = EXTRACT(YEAR FROM sysdate)