I asked the pharmacist this question this weekend about Ibuprofin because they didn't have any infants. In that case, it was 1/2 tsp. for a 1 year old, where as a 2 - 3 yr old gets 1 tsp.
The pharmacist should be able to tell you regarding the Tylenol. I don't know what the mg/ml on the infant's vs children's Tylenol, so the Ibuprofin dosage obviously doesn't help you - just the fact that the pharmacist told me ;o).
I got the Target brand infant's acetomeniphen (sp?) drops. My pedi gives a handout for how much to use since the package says to ask a doctor if under a certain age.
Aaron will now get 2 droppers full per the handout. I remember that 17-13 lb was 1.5 droppers full.
DD -- 5YO
DS -- 3YO