Originally Posted by hairnet

OP, you need to be more specific. Do you want to use a different wheel or put in a new axle with your current wheel? Is it a loose ball hub or cartridge bearing hub? What brand is your hub? This is not an uncommon question so you will find lots of information through a simple Google search. You will surely find something on Sheldon Brown's website. A similar post was made not too long ago here as well.