E.,
A lot of the posts have some great advice about staying positive and looking for things to do in the area you will be moving to.
I noticed your son is an only child (mine is too) and his concerns also need to be addressed because he doesn't have a sibling to go through the experience with.
When you and your husband are looking for a new place to live (either owning or renting) include your son after you have weeded out the definite "no's". Have him go with you to see the possible places to live and the schools in the area.
Contact a number of churches in the area before you move and talk to the pastors. They may be able to pair you with other families who have children the same age and they may be able to tell you more about the town and surrounding area than you can get from a real estate agent.
Your son will want to keep in touch with his friends, so would it be possible to set up some type of social networking site? Here is an article that lists a number of networking sites you can research with your husband and present as options to your son and the parents of his friends.
http://www.socialmediamom.com/2008/02/february-roundu.html
Before you leave you may want to throw a moving party for your son and his friends. Take lots of pictures and get him a scrap book or photo binder to put the photos into for the future. At the party, ask the parents the best way for your son to stay in contact with his friends.
Lastly, visit the local library after you move to Alabama. Good children's librarians provide lots of programs throughout the year for kids of all ages and participating in those programs will give yourself and your son a chance to meet new people and build a new network of friends.
There are negatives to moving away from family and friends, but your son will handle his emotions better if you can look and talk about the positive side of moving. This can be an adventure and can make your family stronger if you approach it in the right way.
Good luck and let us know how the move goes!
-C..