4 wheel cross rotation
This is the preferred method if you tyres are "non-directional" and your spare is not to be used. You take the rear wheels and put them on the front on the same side and take the front wheels and put them on the rear, but crossed over.

5 wheel rotation (includes spare)
This is the preferred method if you tyres are "non-directional" and your spare is to be used. You take the rear wheels and put them on the front on the same side and take the spare wheel and put it on the right rear, then you take the front right and put in the left rear and then you take the left front and make that the spare. 5 wheel rotation is the best way of ensuring that the spare is worn at the same rate as the rest and will get the most mileage out of your tyres.