Yay, something I know something about CJ! (CJ has been an invaluable resource for off-leash training help).
Unrelated, but I honestly don't think any breed but huskies are banned from Iditarod (I can do some research). After, all, the so-called 'Alaskan husky' is a mix of many breeds, some look like hounds or pointers, and are over 75% pointer, others appear more like typical huskies, but generally are more 'village dog' than siberian husky, and others show strong greyhound influence. Almost all Iditarod dogs are leggier, and leaner than Siberians. A few mushers run siberians, but generally haven't done very well. I do remember someone telling me he watched the poodles run the Iditarod. The husky teams trotted by looking fit and happy, and along come the poodles, drooping along, looking miserable. A case of the wrong dog for the job, in my opinion. If I remember correctly, someone also tried running an Irish Setter team in the race a few years back. Same story.
Anyway, in my experience, when training a dog to pull there is nothing more valuable than another trained pulling dog to teach those dogs the ropes. This is pretty much how all sled dogs are trained. If you have anyone local who is a musher or skijorer, going out with them, even hooking one of your dogs up with an experienced dog (of course, they'd need to be compatible), will have much more impact than trying to teach the dog from scratch. Check out Sled Dog Central's site
http://www.sleddogcentral.com/, or the Canadian Skijor site
http://www.skidogs.ca/(a great group of folks from the Ottawa area), for more information, information on local mushers, and on skidogs.ca, good articles on beginning skijoring.
Like Willie said, the dogs can learn the difference between gear, that is, when they are wearing pulling harness, they can pull, when wearing a collar (etc.) they should not pull. Lot's of people (including myself), start their dogs off initially, with just pulling a tire (motorcycle tire works well). Short training sessions, less than five minutes at first, so the dogs knows it is OK to pull, and to teach the basic commands. Nobody uses 'mush!', must musher's use 'hit it' or 'lets go' for the pulling command. There are lots of other fun commands to teach, directional commands, speed up, on by, etc.
I use an X-back harness for skijoring with Tikko. This is the design most commonly used by skijorers and mushers. Someday I'd like to try this harness
http://store.skijornow.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=SN&Product_Code=1111200&Category_Code=DH, but it is pricey.
I'm not sure how much snow you have, but a kicksled might be fun for running three dogs (scroll down to kick sled)
http://www.linendollshappyhuskykennel.com/sleds.htm, if you aren't a skier. You'll also need bungee lines, and a harness for yourself if you skijor. I just use a $15 climbing harness from REI.
I have been SO enjoying skijoring these last few days. My dog loves running in the cold, and for me, there's nothing quite like it. I used the articles on skidogs.ca as a resource getting started with my dog when he was a pup. I've purchased most of my skijor gear at nooksack racing, they are quick to get orders out and will make custom harnesses for your dogs if needed.
Enjoy! This is a really fun winter activity! I find I get the same amount of exercise for myself skijoring, but we can go much farther and faster.