First, you should starve the dog for about 12-24 hours. Secondly, offer the dog a bland diet after the 24 hours. The food should be offered in small portions. Next, take the dog for a check up as vomiting might be a symptom of an illness. For more details, check out http://www.ehow.com/how_2149471_treat-vomiting-dog.html.
A good owner would hold it's ears back :) Dogs just seem to randomly throw up for unapparent reasons. As long as it just throws up a couple times in a row and then is done, there is more than likely no problem. If its a constant thing then you should venture to the vet.
As long as your dog is drinking and keeping down water, you can wait to take them to the vet. If he is not drinking or not keeping water down then get him to the vet soon. He can become dehydrated and that will only make things worse.
As I said, as long as he is drinking and keeping water down, wait to feed him until tomorrow morning. The you can give boiled skinless, boneless, chicken along with either plain rice or plain mashed potatoes. Just give a small amount and you can increase a little bit with each meal. You can feed several small meals the first day. As long as he is keeping this down you can slowly add some of his regular food in the next day. If he doesn't keep that first meal down get into your vet.
Next question, what food are you feeding? There is a recall on some dog foods. If your dog has been eating any of the foods on listed on the link call you vet. http://diamondpetrecall.com/