There are a number of different kinds of brakes used on bicycles including disc brakes (mechanical and hydraulic) V brakes, cantilever brakes and caliper brakes. All are relatively simple to adjust and maintain with just a few basic tools.
Disc Brakes
Adjusting mechanical disc brakes.
Adjusting Hydraulic Disc Brakes
V Brakes
Cantilever Brakes
Caliper Brakes