OMG. Please don't listen to the people who are saying bite him back. Your son is most likely biting from frustration / confusion at the situation with the new baby. You are the adult in the situation and his safe haven - do not consider destroying that trust bond by BITING your own child. We are not living in the middle ages.
Removing toys etc is rarely effective in this kind of situation as you will actually raise his frustration level. Rather, I would discuss with him why he is reacting like this and explain that if he can control himself better then there will be rewards in it for him. Agree what the rewards will be, make it easy for him to earn (small) ones in the first instance when he exercises self control, as he gets in the habit of thinking before he reacts, you can do a star chart or similar so that he gets one special thing at the end of 2+ days of "no biting". This might well involve some special 1-2-1 time with you / your OH as that is probably something he feels is seriously lacking due to the new arrival. Also, asking for help / giving responsibility for certain (easy) tasks can imbue a sense of maturity at this age, but again you need to make it worth his while at least in the 1st instance so that he develops positive feelings towards taking responsibility for himself.
FYI: I was a professional nanny for over 14 yrs (trained at Norland), psychology grad, now studying a masters in counselling-related discipline.
Hope this helps