Conducting composites consisting of polybithiophene and based on porous crosslinked polystyrene as host polymer have been synthetized in the vicinity and above the percolation threshold by oxidative polymerization with FeCl3. Electrical conductivity and thermoelectric power measurements for different degrees of doping have been carried out in the temperature range 80-300 K. The electrical conductivity variations are weakly thermally activated while the thermoelectric power has metallic magnitude with positive sign and increases with temperature. Conduction mechanisms are interpreted on the basis of an hopping model involving bipolaronic clusters.