You can set large hash_area_size and use parallel query. The best way to speed it up is to avoid it if nested loop does a better job.
But before you get into details of this I suggest something like:
Or even old but good one: http://www.amazon.com/gp/product/0072131454/sr=8-1/qid=1151143598/ref=sr_1_1/103-0991714-8826217?ie=UTF8
If you can't get those. Look at least at http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14211/toc.htm
And you don't need ALL CAPS - our monitors are pretty good to read it non-capitalized. ;-)
WHAT IS HASH JOIN IN ORACLE , HOW TO MAKE FAST HASH JOINS
With Best Regards
-- Best regards, Alex Gorbachev