Frequent spitting-up or vomiting could be an indication of gastric reflux in the infant, or possibly, pyloric stenosis or a formula allergy. Reflux, overfeeding, or eating too much are the most common causes.
First, slow down his rate of intake as much as possible, with the slowest-flow nipple you can find, and smaller volumes. Burp him after every 3 ounces that he drinks, and sit him upright during feeding, and prop him up for at least 20-30 minutes after feeding. Take care not to jostle him after he eats for at least the first half-hour.
If this doesn't work, he may need to try taking medications such as zantac and reglan, or prevacid, or have an upper GI series to evaluate his reflux and possible causes. Typically, spitting up is quite common in the early months, and usually resolves after about 6-7 months when babies start sitting up on their own.
I hope this helps!