Source: Expanded Psionics Handbook
You can run on walls for brief distances.
Prerequisite: Wis 13.
Benefit: While you are psionically focused, you can take part of one of your move actions to traverse a wall or other relatively smooth vertical surface if you begin and end your move on a horizontal surface. The height you can achieve on the wall is limited only by this movement restriction. If you do not end your move on a horizontal surface, you fall prone, taking falling damage as appropriate for your distance above the ground. Treat the wall as a normal floor for the purpose of measuring your movement. Passing from floor to wall or wall to floor costs no movement; you can change surfaces freely. Opponents on the ground can make attacks of opportunity as you move up the wall.
For instance, Ma'varkith the psychic warrior has a speed of 40 feet (due to her Speed of Thought feat). She begins her turn standing next to a wall. She moves up the wall at a 45-degree angle ("diagonally") for 20 feet, which puts her 15 feet farther along the wall and 15 feet above the ground. Then she moves 15 feet straight down, ending her move in a 5-foot square adjacent to the wall (she has used up 35 feet of her allowed movement). At this point she takes her attack normally against an opponent adjacent to her, which potentially sets up flanking opportunities for her comrades. If the wall had a ledge within 30 feet of the ground, she could have ended her move on the ledge instead of having to move back down to the floor.
Special: You can take other move actions in conjunction with moving along a wall. For instance, the Spring Attack feat allows you to make an attack from the wall against a foe standing on the ground who is within the area you threaten; however, if you are somehow prevented from completing your move, you fall. Likewise, you could tumble along the wall to avoid attacks of opportunity.