There are several different kinds of worms that a kitten can have. The “rice” means tapeworms, spread by fleas. Diarrhea can also be a sign of worms as can a swollen abdomen. lethargy, “failure to thrive,” and even shortness of breath (heartworms). There are pin worms and hook worms also.
As others have said, the simplest thing is to take the kitten to the vet for his/her shots and take a fresh fecal sample with you (sometimes they can get a sample at the vet’s office but sometimes not – better safe than sorry). The vet can check for worms and, if needed, prescribe the right medication to solve the problem if there is one.
There are lots of good sites to learn about health issues. One I like is Cornell University’s vet school site ( http://www.vet.cornell.edu/fhc/hinformation.htm ), There is a huge list of links at http://www.netcat.org/links.html also, so you can check on individual health issues.
Good luck and enjoy your kitten!