Here is my list for great parenting advise and resources from educational website, schools, and professionals.
 

Reading

Reading Tips for Parents.  Reading Rockets is a great literacy resource.  The link below will take you to a printable guide organized by grade level.
Reading Strategies and Study Skills Support.  Pleasant Valley Community School District came up with a study skills guide for parents to make the most of their child's reading at home.
Building Better Readers Guide.  Florida Department of Education posted a list of suggestions for parents to help build their child's reading skills.
Decoding Strategies.  Finally In First provides a great poster for parents to use as an aid in helping their child read. 
Reading Tips.  Colorado Department of Education created this easy to read brochure for parents.  
Reading Strategies.  Island Trees Elementary Reading Program has strategies for parents to help your children improve their reading skills.
 

 Writing

Writing Tips.  U.S. Department of Education created a list of pointers to think about when readying your child for school.
Writing Resources.  Read Write Think is great for all your literacy needs.  They provide advice as well as games and printables.    
Tool Kit.  LD Online is a sight dedicated as a learning guide for children with special needs and ADHD.  But don't let that scare you because the tools are very informative POWERful!
Beginning Writing Skills.  Get Ready To Read is a great article about what early write looks like and how you can help.
Writing Activities.  This pdf provides parents with ideas and tools to help get your child ready for writing.

Word Study

Word Study Guide.  Carroll County created this awesome newsletter for parents and teachers.  This guide is a great insight as to what your child is or should be learning when working with words. 
Spelling.  Child Development Institute has some great pointers on how to get started, why to get started, and ways to help your child with spelling. 

Preschool

  Word Wall Templates.  DLTK's are a great way to get started exploring words.  These words can be found around the house or within a favorite book.
 

Math

Parent Roadmaps to Common Core Standards - Mathematics.  This site links what children are learning in mathematics for each grade level.  
Preparing for Math.  Scholastic gives a basic outline of concepts to be learned at this age and it's importance.  

Preschool

Early Math.  Get Ready To Read offers advice and great activities for parents to test out at home.
 

Science

Science Matters.  National Science Teacher Association shows busy parents easy ways to bring science into your child's daily life.  
Exploring Science.  PBS Parents gives you a few pointers for helping your child become aware of science around them.     

Social Studies

 
Parents Helping Students.  Michigan.gov offers tips on awareness and relevance in different areas of social studies.  
 
Embrace Digital Education.  U.S. News wrote an article on how to keep in the know about at-home and at school technology.  
Educational Technology.  The Huffington Post hit the nail on the head with its 5 terms parents need to know.  All heard throughout schools and the world.  
Digital Literacy.  Edutopia is one of my favorite sites because of the shear amount of informational articles and resources.  Here they walk parents through the world of tech with tips and linked resources to learn more.