Should I install more fans?

So,I have a 9800GT,i7 920 and a 500W power supply.I have some extra fans but I am not sure whether the power supply will be able to handle them.What should I do?

You'll be fine OP.

It is not always about how many fans you have, but the orientation of your fans. There is a decent amount of science behind airflow :P. Sometimes having more fans can lead to no temperature reductions. It is the nature of the beast, focus on balancing the air that comes in, with the air comes out, and never forget that heat rises!

edit: here is the gist of ithttp://forums.techpowerup.com/showthread.php?t=42853