Personally, I would never EVER do this, for a number of reasons.
The first reason is that during training is a very important time for your dog to bond with you, and learn to trust and look to you for direction.
However, the most important reason is that I wouldn't leave my dog with strangers to be trained. I would have to be there and see what methods are being used. Some board/train centers guarantee results and I would be very worried that methods used may be punishment based or what I consider to be inhumane.
By all means, board your dog. I've boarded my dog before, but not for training and I never would.