No... it's too early for him to have cereal! Here's something I found on Babycenter.
Starting cereal this early in her life isn't a good idea. Despite her weight and the amount she is consuming, her gastrointestinal tract is still immature, and introducing another foreign protein in cereal can predispose her to allergies later on.
At this stage of her physical development, formula is still the only food a formula-fed infant should get. The American Academy of Pediatrics recommends exclusive breastfeeding for the first six months with gradual introduction of solid foods in the second six months for a breastfed baby, and introduction of solid foods between 4 and 6 months for a formula-fed infant.
Some of the signs that your baby is ready for solids are an ability to sit fairly well in a high chair as well as take food off a spoon and transfer it to the back of her mouth. This means the disappearance of the tongue-thrust reflex (where the baby pushes most of the food put into her mouth down her chin with her tongue). The final signal is an interest in food.
With your baby eating so frequently, I can imagine you are thinking she simply isn't being satisfied by the amount of formula she is getting. If she is taking 4 ounces every one to two hours around the clock, she's eating a lot! . If she is spitting up a lot or having diarrhea, she may not really be absorbing all that food. Or if you are mixing powdered formula with too much water, she may be drinking more of it in order to get the calories she needs.
On the other hand, a baby who weighs 12 pounds — which, at her age, is between the 75th and 90th percentiles for weight — needs to eat about 32 ounces of formula a day, give or take a bit, to continue gaining weight. And formula-fed babies also seem to go through growth spurts, at around 2, 3, and 6 months, when they may take more formula for a period of time and then go back to a more "normal" intake.
It might be helpful to determine whether she is really hungry all those times she is eating. Check the hole in the nipple — is it too big? Is she drinking too fast, and not getting the amount of sucking time she needs? Feeds should take about 20 minutes with lots of hugging and snuggling with Mom or Dad. This helps satisfy both her nutritional and nurturing needs. Will she take a pacifier or suck on her thumb or fingers instead of taking a bottle? Can you distract her from her bottle by playing with her or doing something else? Are you, perhaps, encouraging her to finish the bottle instead of taking it away once she indicates she is no longer interested by pushing it away or biting on the nipple?
When you do start solid foods, start gradually, allowing your baby's GI tract to adjust to each new food before starting another. Rice cereal mixed with breast milk or formula is generally baby's first solid food. Then wait a few days and try something else, such as a green vegetable. After a few more days, you can introduce another cereal such as oatmeal, or another vegetable or a fruit. This way, if your baby has a reaction to anything, you will know right away what it is. While which foods you start first is not terribly important, the usual progression is cereals, vegetables, fruits, and then meats. Foods considered potentially allergenic, such as cows' milk, eggs, wheat, and fish, should not be started until the baby is closer to a year old.