--accessible cursors

SELECT oc.user_name, st.sql_text 
FROM     
v$open_cursor oc, v$sqltext st 
WHERE    
oc.address    = st.address AND      
oc.hash_value = st.hash_value 
ORDER BY oc.user_name, st.piece 

For performance reasons, pl/sql cursors are cached for future reuse .         so once you use them up they will be added to LRU list of cursor table.         Hence you can see them in v$open_cursor.          

--actual open cursors
select sum(a.value), b.name       
from v$sesstat a, v$statname b      
where a.statistic# = b.statistic#      
and b.name = 'opened cursors current'      
group by b.name