A friend of mine has a kitten and thinks she found what may be a tooth by his food bowl. Do kittens have baby teeth that fall out like human baby teeth, and at what age does this happen?
Yes, cats have "baby teeth".
According to this veterinary site, teething occurs between 3-7 months of age.
It's not uncommon for a cat to sport two sets of upper canines ("fangs") for a while. Provided it isn't causing pain (they will be careful eating, gums will be red/swollen, and/or if you touch the tooth they'll react strongly), it's rather endearing.