Glycolysis - Occurs in the cytosol and does not depend on the presence of oxygen. It therefore occurs in both aerobic and anaerobic respiration. In glycolysis, glucose (C6H12O6) is broken down into two pyruvate molecules (each has three carbon atoms). Hydrogen ions are also attached to NAD carriers (when carrying H+ they are called NADH). There is a net gain of 2 ATP.

Krebs Cycle - Occurs in the matrix (between the membranes) of mitochondria. Oxygen is not used but the process is dependent on oxygen being present for the next stage. The two pyruvate molecules are broken down and carbon dioxide is released. More hydrogen ions are carried by NAD and FAD (when carrying H+ FAD turns into FADH2). There is a net gain of two ATP.

Electron Transport - Occurs across the inner membranes of a mitochondrion. These are called crystae. The hydrogen ions in the previous two stages are released from NADH and FADH2 and are then carried through proteins called cytochromes and eventually are used to resynthesise ATP from ADP + Pi. 32-34 ATP are gained from the process. The hydrogen ions are then bonded to oxygen to form water. NAD and FAD are recycled.

I don't think you need to know that much - the VCAA gives a very lose definition and says that you need to know the inputs and outputs of each stage in general terms.

To give you a more simple description:

Glycolysis - Occurs in the cytosol and does not depend on the presence of oxygen. One glucose molecule is broken down to two pyruvate molecules and there is a net gain of two ATP.

Krebs Cycle - Occurs in the matrix (between the membranes) of mitochondria. Two pyruvate molecules are broken down, carbon dioxide is released. There is a net gain of two ATP.

Electron Transport - Occurs across the inner membranes of a mitochondrion. Oxygen is an input. 32-34 ATP are released as well as 6 water molecules.