A good blog with podcasts for math lessons using the smartboard. Winner of an Edublog award, this site offers video and voice lessons for you to use as well as hints and tips to make your lessons more interactive.
SMARTBoard Lessons Podcast

Use Mathslice to teach or learn everything from Pre-Algebra to Algebra II, Geometry to Polynomials, take practice SATs and PSATs, use worksheets from basic math to place value,statistics to scientific notation. All math GLEs represented. Highly recommended.

Great informational videos created by kids and teachers... Great to turn on at the beginning of class as a refresher or to post a link to for homework help outside of the classroom. All GLE's represented, all grade levels... Constantly changing!
Geometry 3-D Shapes. Every object you can see or touch has three dimensions that can be measured: length, width, and height. Students are able to see all three of these dimensions with the interactive 3-D models presented here. Recommended for grades 6-8.

Kings list of on-line math activities. A veritable library of interactive math sites. Tesselations, fractions, graphing, integers, geometry - and much more. Hits all the GLEs from grade 5-8 for Number and Operations, Geometry and Measurement, Functions and Algebra.

NECAP GLEs grade 5 M(F&A)-5-4 - Multiplying binomials

Cool math 4 Kids, with it's black background and neon colors bills itself as " An amusement park of math and more -- especially designed for kids and FUN, FUN, FUN!" It features an online math dictionary, and a geometry and trigonometry reference area. GLEs addressed: Functions and algebra grades 5-6

Fact Monster is a great site that offers many interactive games for all students in grades K-8. This site offers games and activities that help reinforce lessons that are being taught in the classroom. There are many math GLE’s addressed for grade 6 including N&O, G&M, F&A, DSP, and PRP.