All of this is good advice. There is a good chance the kitten has worms or other illnesses. Take him to a vet for a checkup. Most cats choose their owners and it looks like this one has chosen you. Keep him inside (outside cats have a much shorter lifespan that indoor cats), take good care of him, give him lots of love and you will be rewarded with a loving, entertaining companion.
P.S. You've greatly increased your karma points, don't toss them away.