huge table / bitmap indexes

Hello All

is in postgres any possibility to create bitmap index ? I have big
(~12 000 000 records) table where one field have limited count of
values. Many queries use this field in where section. I thing that
bitmap index will by better than BTree.
How i can optimize select on this table ?

Thanks - Cure

--
The poor player plays the opponent's game for him.
cure mailto:cure(at)icpnet(dot)pl