I personally think it is better for kids to know what their diagnosis is, especially those high functioning enough to understand. But I think it is key to approach it in a way that the label "autism" is just an explanation for his difficulties, and not seen as "bad." I tell me daughter that "autism is a reason, not an excuse." If you do decide to tell your son, you may want to share stories of successful people with autism, such as Temple Grandin. Also, there is a great book written by a 13 yr old British Aspie called "Freaks, Geeks, and Asperger Syndrome." The author is Luke Jackson. It is full of advice for other aspies. I have been wanting my daughter to read it without success, but it is useful as guidance in working with our kids I think.

I would tell him. I know that my son was coming home in tears because he felt "different" and didn't understand why. When we got the diagnosis of Asperger's, it was a huge relief for him. We actually saw improvement in his mood and behavior because now he understood what was different about him.
We have also stressed that it just means that his mind is wired a bit differently. There is nothing "wrong", just different. Definitely point out famous people with Asperger's and let him know that he can be very successful.
A fun way to introduce Asperger's to kids is the book "Dude I'm an Aspie" by Matt Friedman. You can buy it from www.lulu.com. You can also see the full thing at http://www.wrongplanet.net/postt112787.html wrongplanet has lots of forums for people dealing with autism spectrum issues.
Good luck.

I told my child. It helps him to cope because he knows he is different. In respose to your question...I asked Loud to weigh in on your question. He said "Its not a big deal if you know why your diffrent, but its aggrivating when you dont know what its called so you cant talk about it." Hope that helps. Loud is 10. We told him when he was 7.

It's a good idea to tell him so he knows what is going on. He may not understand fully what it is yet, but this is an ongoing conversation. He probably already knows his mind works differently and he behaves differently than others and has to learn behaviors to compensate and deal with it. Check out the Hidden Curriculum.

Wow what terrific, insightful and loving comments. Glad I found this site and you.
I am the mother of a 20 year old high functioning autistic daughter, 2 more AD/HD kids, ADD husband and I'm autistic (diagnosed Aspie but I think that's because I'm in my fifties and can fake it/pass well enough) so we speak "different" in our house. I'm all for disclosure not for the excuse part (my husband felt that way for a long time...diagnosis as excuse...not anymore though). Knowing...as GI Joe cartoons said years ago...is half the battle. The literature available has been incredibly helpful for recognizing trigger situations and developing pragmatics. I use the word pragmatics (probably incorrectly) as tools to use when going into stressful/difficulty situations. That's been the most helpful aspect of talking diagnosis in our house.
From gum chewing; iPods, playlists & Bose headphone; wearing the same clothing material daily; melatonin for sleep issues; learning meditation techniques centered around mindful breathing; to discussing literal English speakers versus contextual English speakers as "two different cultures" NOT good versus bad...we've changed how our family interprets everything depersonalizing our "autistic" differences. This has allowed our entire family to recognize behaviors in themselves, siblings, parents, friends and teachers (you'd be surprised how many teachers have "autistic" tendencies. We've hired "friends" older more aware kids who "get" my kids. Conversely we've also had our kids volunteer to help younger kids. That gives them insight into their own behavior...as Einstein said “I never teach my pupils; I only attempt to provide the conditions in which they can learn.” It's true you can't pass wisdom on you can only set your kids up in situation where they experience things and support whatever they take from it...like teaching the color blue...talk about it all you want but until a visual is given you don't understand completely.

Jessica Kingsley Publishing is a tremendous website for books, etc. http://www.jkp.com/ have a look. Best Wishes!