  An effective field theory is derived for the ferromagnetic transition of
diffusive electrons at T=0. The static disorder which leads to diffusive
electron dynamics induces an effective long-range interaction between the spins
of the form 1/r^(2d-2). This leads to unusual scaling behavior at the quantum
critical point, which is determined exactly. The crossover from this quantum
fixed point to the classical Heisenberg fixed point should be observable in
ferromagnetic materials with low Curie temperatures.
