We present a measurement of the unitarity triangle angle phi(3) using a Dalitz plot analysis of the K-S(0)pi(+)pi(-) decay of the neutral D meson from the B-+/-->(DK(*)+/-)-K-(*) process. The method exploits the interference between D-0 and (D) over bar (0) to extract the angle phi(3), strong phase delta and the ratio r of suppressed and allowed amplitudes. We apply this method to a 357 fb(-1) data sample collected by the Belle experiment. The analysis uses three modes: B+-> DK+, B+->(DK+)-K-* with D-*-> D pi(0), and B+-> DK*+ with K*+-> K-S(0)pi(+), as well as the corresponding charge-conjugate modes. From a combined maximum likelihood fit to the three modes, we obtain phi(3)=53 degrees(+15 degrees s)(-18 degrees)(stat)+/- 3 degrees(syst)+/- 9 degrees(model). The corresponding 2 standard deviation interval is 8 degrees <phi(3)< 111 degrees.