Normal airflow thru a case (well, normal for me anyways
yes, that is what my hair looks like today) is in from the front, out thru the back. I prefer negative pressure, meaning more air being exhausted by fans than pumped in by fans. My Cooler Master HAF 922 case has one huge front intake, a nice size rear exhaust, and a really huge top exhaust. Board temp will never get above 50c. CPU runs maybe 65c with all four cores running Folding @ Home 100%. Cooler Master Hyper 212 cooler. The side fan deal, if I had one (I only have a mesh grill on the side) it would be pulling air in like Jerry and Kanawha said, pointed at the video card.
Video cards are are a different subject. If you have an Nvidia card, get the EVGA Precision Tool http://majorgeeks.com/EVGA_Precision_d6209.html
It will let you see the card temps and also you can increase the fan speed. I run my fan about 85%, kinda noisy but Folding runs the card at 99% usage. That's pretty brutal, so I gotta cool it down somehow.
I also have all the fans in the case and on the CPU running at 100%, nothing is temperature controlled. But that gets into where and how the fans are connected, and also some motherboard BIOS settings, which you may not be ready for, young Padawan.
Oh, and with all three of my PC's running Folding 24/7, I don't need a room heater at night.