On November 3, 2000, about 1225 eastern standard time, a Piper PA-34-200, N1519T, registered to and operated by Phil Air Flight Center, Inc., experienced a loss of directional control on landing and collided with a taxiway sign at the Daytona Beach International Airport, Daytona Beach, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 instructional flight. The airplane was substantially damaged and the certified flight instructor (CFI) and pilot-rated student were not injured. The flight originated about 1030, from the Daytona Beach International Airport. The CFI stated that the purpose of the flight was a final review for the student who was training for the commercial, multi-engine course. After departure airwork was performed, the flight then proceeded to the Flagler Beach Airport where the student performed three uneventful landings. The flight returned to the departure airport where the student performed a practice VOR approach and a practice ILS approach. During the ILS approach when the flight was at 400 feet mean sea level (msl), she (CFI) had the student remove his hood and advised him that the flight was cleared to land. At about 100 feet, "a wind gust sent us high and I saw how the airplane slowed down. At that time I took over the controls to correct for it adding power. After doing that the airplane started turning to the left. [It seemed] that the left engine did not react fully and the left turn continued." She retarded the throttles; the airplane touched down on grass between taxiway "N" and runway 7L. The airplane remained on the ground and the right wing collided with the taxiway "N3" sign. The airplane came to rest on taxiway November. A METAR weather observation taken at the Daytona Beach International Airport, at 1253, indicates in part that the wind was from 030 at 9 knots; there were no wind gusts reported. Additionally, a weather observation taken at 1153, indicates in part that the wind was variable at 4 knots; there were no wind gusts reported. A copy of the METAR observations is an attachment to this report. Examination of the accident site by a Federal Aviation Administration (FAA) inspector revealed a scrape mark on taxiway "N2" associated with the left wing tip. The airplane touched down on taxiway "N2", and skidded off the taxiway onto grass between runway 7L and taxiway "N." The right wing of the airplane collided with taxiway "N3" sign. Taxiway sign "N3" was "broke loose from cement pad. Only one mounting leg broke at shear point, the remainder of mounting legs broke away from pad by breaking cast mounting plates." Postaccident, an engine run-up was performed with no discrepancies noted. A copy of the FAA inspector statement is an attachment to this report.