Do you think your child is gifted? Now that sounds like a loaded question, but actually it isn't. Parents are usually the best judge of whether their child is gifted.
If you know your child is gifted, or have been wondering if they are, a great place to explore is Hoagies. (Yes, like the sandwich.) It is a great web site for all things gifted. There is a great deal of information on homeschooling, the different levels of giftedness, and many articles about the needs of gifted children. I highly recommend it. I learn something each time I stop by.