Both of my kids had GERD (acid reflux) as babies and never grew out of it. The kind of spitting up your son has can be dangerous b/c they can aspirate the fluid/food into their lungs. And some babies can have irritation of their stomach and esophagus even if they aren't crying all of the time. The first thing I would try is to change formula. Lots of babies have sensitivities to dairy protein and that can really make them spit up a lot. And be really careful about what solids you give him. Try to stick to things that are less acidic (peaches are the worst). And like other people have said, smaller meals really help too. Keep him upright for 30 minutes after feeding. Don't feed him or give him a bottle right before he lays down for a nap.
Most babies grow out of reflux by one year and it tends to get better around the time they are sitting up on their own. But you can ask your ped for a referrla to a pediatric GI. They are trained to treat reflux and will know (even w/o tests sometimes) if your baby needs meds or if it's 'normal'.
Here is a great website with lots of info and help:
www.reflux.org
Also, feel free to e-mail me thru my profile if you have questions. Good luck!