Your PlayerStart is a camera, and you use things like:
void AddPlayerBodyForce(float afX, float afY, float afZ, bool abUseLocalCoords);
Pushes the player into a certain direction. Note that you need values above ~2000 to see any effects.
afX - amount along the X-axis
afY - amount along the Y-axis
afZ - amount along the Z-axis
abUseLocalCoords - If true, axes are based on where the player is facing, not the world.
void MovePlayerHeadPos(float afX, float afY, float afZ, float afSpeed, float afSlowDownDist);
Changes the position of the camera on the player's body.
afX - amount along the X-axis
afY - amount along the Y-axis
afZ - amount along the Z-axis
afSpeed - speed at which the change happens
afSlowDownDist - distance at which to start slowing down (prevents the head from abruptly stopping)
You may need to put them in a timer which loops however if you want to make it move for quite a while.