Mathematics and Multimedia a blog about mathematics topics, with resources, software tutorials and teaching tools

Mathematics Illuminated a multimedia site from Annenberg Media that helps teachers increase their expertise and teaching methods in mathematics

Middle School Portal 2 a social networking site for middle school math and science teachers

NCTM Online  (The Unofficial National Council of Teachers of Mathematics Online Member Network)

Web 2.0 for Math Educators a wiki on using Web 2.0 for math instruction

Web 2.0 Math Tools a collaborative Web site with Web 2.0 resources that support math in the classroom