Speaks later than most children
Slow vocabulary growth, often unable to find the right word
Difficulty rhyming words
Trouble learning numbers, alphabet, days of the week, colors, shapes
Extremely restless and easily distracted
Trouble interacting with peers
Difficulty following directions or routines
Fine motor skills slow to develop
It's important to realize that parents will see some of these signs in most children at one time or another. However, if you see several of them over an extended period of time, it might be worthwhile to have LD ruled out.
You can get a free booklet about learning disabilities from the Coordinated Campaign for Learning Disabilities by going to their website at www.aboutld.org or calling them at 1-888-GR8-MIND. If you decide to have your son formally evaluated, CCLD can help you locate a professional in your area who can help or you can ask your school system to assess him.
Many of the behaviors you are describing are not unusual for a five-year-old boy, but they should not be overlooked. There are many things you can do to help your son with early reading skills right now. If you go back to the home page of FamilyEducation.com, you will find many ideas for working with your son at home. I also recommend that you have a look at Susan Hall and Louisa Moats' book, Straight Talk About Reading: How Parents Can Make a Difference During the Early Years.