Similac sent me this guideline in the mail:
Birth-1 week 6-10 feedings per day, 2-3 oz, 21 oz (average) in 24 hrs
1 week-1 month 7-8 feedings per day, 2-4 oz, 23 oz (average) in 24 hrs
1-3 months 5-6 feedings per day, 4-5 oz, 25 oz (average) in 24 hrs
3-6 months 4-5 feedings per day, 6-7 oz, 30 oz (average) in 24 hrs