cv joints-need help

I know it has already been talked about but it would not let me search cv and nobody refers to them as constant velocity joints. Anyways, I am starting to get the click and need to switch the axle out. Huck told me about a tool that I needed to get a pin out somewhere. What is that tool. Also how hard is it to get a hold of a new half axle? And where should I go? Any help would be much appreciated. Thanks!