  We present the first measurement of the faint end of the QSO luminosity
function at z=3. The QSOs, which range from M_1450 = -21 to M_1450 = -27, were
discovered in 17 fields totaling 0.43 deg^2 using multicolor selection criteria
(the Lyman break technique) and spectroscopic followup. We find that the
faint-end slope of the luminosity function is beta_l=1.24 +/- 0.07, flatter
than the value of beta_l=1.64 +/- 0.18 measured at lower redshift. The
integrated rest 1450 A UV luminosity of z=3 QSOs is only 50% of most previous
estimates, and is only ~8% of that produced by Lyman break galaxies at the same
redshifts. Assuming that ionizing photons from faint QSOs are as successful in
escaping their host galaxies as bright QSOs, we estimate the total contribution
of QSOs to the ionizing flux J_912 at z=3, J_912=2.4*10^-22 ergs/s/cm^2/Hz.
This estimate, which we regard as an upper limit, remains consistent with rough
estimates of J_912 based on the Lyman-alpha forest "proximity effect."
