Does sound like a control issue, bless him. It might be worth concentrating on this and giving him small tasks or chores or 'things' that he is responsible for but by involving the baby too - so when the baby is being dressed he chooses the outfit for his little brother. If you are bathing the baby let him choose some toy's for the baby to 'play' with, that sort of thing.
I think it's also important to stick to any kind of routine that you previously had with your eldest coz I am sure when the new one arrived it threw everything into chaos a bit and probably unsettled him.
I found this on the net :
http://www.juniormagazine.co.uk/page/juniormagazine?entry=jealous_toddlers_by_rachel_raggHope things improve for you soon!