Science Sites
This   site it hosed by NASA and covers many exciting topic in Earth science.  There is a moon phase game, a water cycle   tutorial, a reason for the seasons movie, and many other great facts about   many topics.  The home page offers   links to projects as well where students can print templates and directions   for creating scale satellite models. This site is a tremendous source for   elementary science teachers.
1;   http://kids.mfc.nasa.gov
2. http://www.scienceteacherstuff.com/ Science   Teacher Stuff is a site that is a tremendous resource for locating other   internet sites relating to many topics in elementary (and through grade 12) science   sites on the internet.  There are   sections for electricity, force and motion, matter, sound, light, and heat to   name a few.  They have categories for   just about all  science topics covered   K-12.  From the home page, one can   view a list of science publications, science supply vendors, science   professional groups, discussion groups, technology, math,  etc.    I found some of the links to be invalid; however, there are quite a   few links organized by topic for one to locate some information without   having to use a search engine.
3.http://www.cws-scf.ec.gc.ca/hww-fap/index_e.cfm Hinterland's   Who's Who is maintained by the Canadian Wildlife Service.  This site allows you to view or print fact   sheets for birds,   mammals, and other related topics.  Each fact sheet describes the appearance,   life history, and habits of a Canadian bird or mammal or else discusses a   wildlife-related topic such as bird feeding or endangered species.  The fact sheets are great resources for   discussing animals and ecosystems and animal adaptations and habitats.  The site also has other links to   environmental information.
4.http://mbgnet.mobot.org/index.html Maintain by   the Missouri Botanical Garden, this website lists the Biomes of the   world.  It is a great resource for   ecosystems units.  This site has lots   of great information ? and is written in a very clear and concise format for   older elementary students.  Each   section is organized into manageable pieces of information enabling students   to locate information very easily.    There is more information in this one website than any other that I?ve   ever encountered.
5.http://www.billnye.com Bill Nye the   Science Guy is a very interesting and engaging man who presents science   topics in a clear and concise manner. His T.V. programs air on digital cable   and satellite TV.   This site allows   you to download PDF files for various episodes.  You can find the episode topics easily on the website.  I really do not like the Flash   presentation as I have a slow internet connection.  The PDFs have a brief summary of the episode and lists   resources.
6.http://www.need.org/guides.htm
Literacy Sites
6.   http://www.carolhurst.com/ Carol Hurst   is a literature site that contains useful information on many topics for   literacy.  This site includes a useful   table of contents so that you can see all the links on one page to facilitate   ones search.  She includes reviews and   lesson ideas for certain titles as well as literature ideas for several   topics.  I find this site useful as a   resource finding ideas to include in a novel study; however, there are not   too many titles included on this site for immediate use in the   classroom.  This site is a good start   to locate information on different topics, but I found it to be limiting in   scope.
This site   hosts useful lessons for using the 6 trait writing process.  You can search for lessons by grade level   by the trait that you would like to work on with your students.  There is also other information that is   useful for the students to understand what each trait stands for and what   types of things are assessed in any given trait.  This site also gives teacher support for getting started using   the 6 trait writing in the writing classroom.  I use this site periodically to look for specific lessons.
7.http://www.nwrel.org/assessment/assessment.asp
8.  http://www.aesopfables.com/ This site   has hundreds of fables ready to copy and print for use in the classroom.  There are fables from Aesop and others as   well as fairy tales by Hans Christian Anderson.  I find this free site helpful to use fables in my   classroom.  I usually copy and paste   the fables from this site into a Word document so that I can format them anyway   that I like.
four blocks for upper grades
Math Sites
http://www.mathmastery.com/ Math Mastery   is a great resource challenging students in grades 4-8 with daily problems to   solve as well as for drill and practice for any math operation.  The daily challenges are very challenging   and the drill and practice is like a beat the clock.  This site allows students to track their   highest score with each drill.  There   is also a link for activities to do at home that changes weekly.  I like that I can use this site for good   math students and also for those who require remedial drills for their   multiplication tables. 
10. http://www.illuminations.nctm.org Maintained   by the National Council of Teachers of    Mathematics ? this site hosts many great math resources and is   organized by grade level, K-12.  There   is an extremely cool link to using interactive multi-media math lessons   (geometric solids and graphing using spreadsheets, to name a few.)  There are links to math internet sites   that the NCTM stands behind, many lesson plans, resources for teachers on   research, and the ability to create your own interactive online math   lessons.