Dorothy van den Honert has some amazing resources over at "Reading from Scratch" for helping dyslexic learners.
One thing she has on her website is a free diagnostic test to help you know whether your child might be dyslexic.
She also provides a fascinating history about how we finally learned about what is going on in the brain of folks with dyslexia. Hint: dyslexics DON'T reverse their letters and dyslexics are intelligent!
She asserts that phonics is one key part of helping dyslexic learners, along with with other brain retraining steps. Here are some spelling rules that are part of that phonics instruction and can be useful to all types of learners.