Somehow you are supposed to be able to repoint brick with a pointing trowel. This theory has not worked out for me. Most of the mortar wound up on the ground and not in between the bricks. A better method for me was to take a gloved hand, grab a glob of mortar and smash it into the bricks, smooshing it into the cavities.
3/2006 Update:Link for repointing is dead.