For research...

Marcopolo - an extensive educational resource with links to partners in Reading & ELA, Mathematics, Science, Humanities, Geography, Economics, and the Arts.

Google

Yahoo  

Wikipedia - Free Wikipedia Encyclopedia

• Cross-curricular...
  
  PBS - online resources and activities for children, teachers, and parents...also featuring popular characters like Arthur, Sesame Street, Reading Rainbow, Caillou and more at pbskids.org and pbskids.org/go
  
  Funbrain- interactive games in math, reading, and more for grades K-8
  
  BBC schools- a British website with interactive activities for preschool (ages 18 mos - 5 yrs), primary (ages 4-11), and secondary (ages 11-16) aged children. Includes curricular areas like numeracy, literacy, geography, science, history, art, music and more
  
  Enchanted Learning- child-friendly information on various topics; great resources for teachers at a minimal cost
  
  

• For math and logic...
  Funbrain - the math arcade is a fun way to practice math skills and problem solving (grades K-8)
  
  Math.com - from basic math to calculus
  
  AAA Math - learn, practice, play, and explore (grades K-8)
  
  Cool Math - brain benders, geometry, long division lessons, fractions, decimals, times tables, arithmATTACK, number monsters, and more
  
  Superkids - logic games including towers of hanoi, battleship, squares, checkers, and more
  
  National Library of Virtual Manipulatives. Visit the "Virtual Library" for exciting online activities with Number & Operations, Algebra, Geometry, Measurement, and Data Analysis & Probability. Appropriate for grades Pre-K through 12.
  
  For Reading & English Language Arts:
  
  Dictionary - definitions, antonyms, synonyms, and encyclopedia entries
  
  USA Today - online news from USA Today