Originally posted in the old Capture website, at capture.beyondunreal.com, now defunct. I had a copy in my backups.
The target location you want to boost to has to be the adjacent to a wall that you can hit at a 45 degree angle. As you hold you run key forward into the wall at that 45 degree angle, hit a strafe direction away from wall with the jump key at the same time, twice. It'll take some practice, but you should here a unique mix of the player “grunt” noise, and it will propel you to your target location, as long as it is not too high. The boost dodge can be used effectively to get to areas that you normally wouldn't be able to without a translocator (i.e., while you're a flag runner). For example, try running to the middle of CTF-Orbital2, and run at that magic 45 degree angle towards the sides of the middle ramps with the shield power up. If you start a boost dodge right as you hit the area that the light touches the walls, you'll be able to boost dodge up to the higher walkways that lead to the upper levels of each base. This can be very useful for giving your pursuers a bit more of a challenge! Try out your boost dodging skills in your favorite levels, and I can almost guarantee it will provide you with some route you'd have never thought of before.