Weld a short length of 1/2" threaded rod into the guide pin:
http://www.northstarperformance.com/img/guidepin1.jpg

Then, place a piece of pipe over top of the pin that is slightly higher than the edge of the pin. A washer on top, followed by a 1/2" nut, and turn with a wrench until the guide pin pulls out.
http://www.northstarperformance.com/img/guidepin2.jpg

It's very easy and takes the pain out of removing the pins. Since these pictures were taken I now use a plate of sheet metal to protect the surrounding surfaces, but none of the sparks/weld spatter have touched the block surfaces at all.

I used a mig welder (with insufficient shielding gas as you can tell in the pic) but a stick welder or flux-core wire feed unit would work as well. The mig is just so much easier to work with. Stick welders (240volt) generally throw out too much heat for welding thin metals, but it's backed by the 1/2" rod so it should work well. If anyone tries this with a stick welder, just be careful- one touch of the rod to the deck surface will likely do irreversible damage.