Racing pedals generally just install on top of the original pedals. Your gas pedal is plastic and has nothing that needs to be taken off, and installing a pedal ontop is as simple as taking the pedal and securing it down with self-tapping screws.
The brake pedal is more fun, as it is made of steel. You remove the Rubber top part (you just pull it off, it is slid over). From there you have to drill into the pedal to make a hole for the screws, and then you bolt it on.
http://www.ultimatepedals.com does a really good job - I have a set from there, and they were custom cut to match the pedals. Made from high quality aluminum - I like them a lot! ...im at work and don't have pics, but if you want I can try to take them when I get home.