The pilot, who was training for her certified flight instructor (CFI) certificate, was returning to the airport. Following the first touch down on runway 7R, she felt that "...something was wrong with the rudder pedals." She felt a slight tugging to the right, but once the airplane was airborne again she no longer felt this tugging. She then retracted the landing gear. As she was on downwind, she extended the landing gear and the green light for the nose gear momentarily flickered but became a solid green light. As she turned onto the final leg of the traffic pattern, she verified that the landing gear were down and locked. Upon touchdown, she immediately felt the airplane tugging to the right side and decided to abort the takeoff. The pilot began to pull the power back to idle and apply braking, while leaving the flaps extended. As she applied the brakes, the airplane pulled to the right which felt to the pilot like the right brake was locked. The pilot removed her feet from the brakes evenly and the airplane turned quickly to the right. She attempted to correct with left rudder inputs; however, the airplane collided with a sign and sustained substantial damage to the right wing. The pilot indicated that a CFI at the flight school told her that two of his students reported uneven braking in the airplane. The CFI was interviewed by the National Transportation Safety Board investigator. He indicated that during two dual, instructional flights, his students reported uneven braking. When the students reported the problem, he conducted the following landings. The CFI did not experience any braking anomalies or directional control problems with the airplane. A Federal Aviation Administration inspector responded to the accident site. The inspector indicated that there were marks on the runway, consistent with the airplane touching down with the landing gear not pointed directly down the runway. Inspection of the airplane did not reveal any mechanical malfunctions with the landing gear or braking system. Review of the maintenance records did not indicate any recent discrepancy reports involving the landing gear or braking system.