All air shocks sold over the counter are valved for rear operation and won't provide nearly enough damping in a front application. If its strictly off road, go for it, but don't come beat me up after you've crashed your truck into a bridge
But having said that... if you know what you're doing, its pretty easy. Go to the parts store and ask for the shock catalogs. In the back they list every shock with their dimensions, including compressed height, extended height, bolt mounting pattern, the works. Just find the dimensions on your stock application, then thumb through the catalog to find an air shock with the same dimensions. You'll have to do some fabrication because the original front shocks have completely different mounting styles than the rear shocks. You won't find a direct bolt-in, but you can find something close.
For my money ($74 to be exact) I bought air lift helper bags for my off-road scout. Much less work than air shocks would have been, and stronger too since the shock mounts aren't designed to carry weight.