National Council of Teachers of Mathematics
The Math Forum: Prime Numbers
Explains what Prime Numbers are and how to find them. Includes a list of primes under 200 and discusses the Sieve of Eratosthenes. This site has numerous links to other internet sources regarding prime numbers.
Other
Help With Fractions: Prime Numbers Chart
Prime and composite numbers are defined on this website. A prime number chart is also included for all prime numbers under 10,000.