The extended phase space method of Batalin, Fradkin and Vilkovisky is applied
to formulate two dimensional gravity in a general class of gauges. A BRST
formulation of the light-cone gauge is presented to reveal the relationship
between the BRST symmetry and the origin of SL(2,R) current algebra. From the
same principle we derive the conformal gauge action suggested by David, Distler
and Kawai.Comment: 11 pages, KANAZAWA-92-1