On October 30, 2007, about 0841 mountain standard time, a Piper PA-28-181, N309PA, was taxiing for takeoff when it collided with a second Piper PA-28-181, N923PA, that was standing with its engine operating at Deer Valley Airport, Phoenix, Arizona. The first PA-28, N309PA, sustained substantial damage, and the second PA-28, N923PA, sustained minor damage. There were no injuries to the student pilot, the sole occupant of the first PA-28, or to the flight instructor and student pilot, the two occupants of the second PA-28. Both airplanes were being operated by Pan Am International Flight Academy of Phoenix as instructional flights under 14 CFR Part 91. Visual meteorological conditions prevailed and no flight plans were filed for the planned local flights, which were originating when the accident occurred. Information provided by the Federal Aviation Administration inspector who responded to the scene of the accident and the pilots of both airplanes indicated that the first PA-28 was in the run up area adjacent to taxiway C1 at the end of runway 07. The second PA-28 was holding short of runway 07 on taxiway C1, in front of the first PA-28. The local controller asked the student pilot of the first PA-28 if he was on taxiway C2, and the student pilot responded that he was on C2. The controller cleared the first PA-28 for takeoff. The student pilot taxied forward and attempted to maneuver around the second PA-28 in order to reach the runway. The right wing of the first PA-28 passed under the left wing of the second PA-28 and then contacted the propeller of the second PA-28. Contact with the propeller severed the outboard 1 foot of the right wing of the first PA-28.