Yes, look it up. There should be information all over the net about it. If it's just for school, then the stuff off the net (always taken with a grain of salt) should suffice. If it is for personal reasons, I would advise seeing a health care professional for situation specific advice.
In short, a person with Klinefelter's is NOT a hermaphrodite, but a male usually with an extra (so-called female) X chromosome, so that he is XXY (normal is XY). However, there are variations on the theme (like XY/XXY).
An XXY male usually is infertile. He may or may not have developmental delay: ie. many Klinefelter's patients may have learning disabilities but some are of relatively normal intelligence (unlike Down Syndrome). It's probably a bad idea to compare it to Turner's Syndrome (X0) since they are quite different syndromes.