ASCE 7-05 Table C3-1 lists 4" clay brick wythes at 39 psf as a minimum design dead load, and "exterior stud walls with brick veneer" at 48 psf. I generally use 40 for the brick and add up the components of the stud wall system (using 48 as a minimum regardless).
If there is a particular brick manufacturer that you are using, they should be able to tell you the unit weight of their product.