It's best to consult an Engineer to determine how deep your foundations must be and whether there needs to be steel reinforcing.  This is all dependent on what the soil conditions are and whether you intend building a single or multi-storey building.  The minimum requirements for a foundation are 230mm deep x 600mm wide concrete footing, with 5 course of brickwork (reinforced with brickforce every course) to floor level.  However I can not stress enough the necessity of getting advice from an Engineer before you start to build.