Best Profiler for PostgreSQL

Hi,

I am running PostgreSQL-8.4.0 on a SMP Server which has 32 processors
(32X2=64 cores). I am working on database parallelism and I need to do
profiling in order to find the relevant parts to parallelize. I wrote
15 queries which are performing select, sort, join, and aggregate
functions and  I want to  profile these queries and try to understand
where postgresql spends more time and then I will try to parallelize
source code(time spending parts) by using openMP. But I need guidance
about profiling tool, which is the best tool to profile queries. I
used gprof but I want to profile with a more advanced tool. Options
are oprofile and valgrind.

1) I can not decide which best suits for query profiling. oprofile or
valgrind?

2) Also for both I can not find documentation about profiling steps.

Please help,
Reydan