Speeding up operations

hi...
im on a project using Postgres. The project involves, at times, upto
5,000,000 inserts. I was checking the performance of Postgres for 5M inserts
into a 2 column table (one col=integer, 2nd col=character). I used the
Prepare... and execute method, so i basically had 5M execute statements and
1 prepare statement. Postgres took 144min for this... is there any way to
improve this performance? if so, how? btw, im using it on a SPARC/Solaris
2.6.
thanx in adv
rahul

P.S: Kindly point me towards any relevant documentation as well.