I found it a lot easier than most people expected, my first was such a good baby, and when the second arrived, he really wasn't interested in the baby at all. I think he was too young to even think about jealousy. Now they are 9 & 10, they get on really well, share interests, friends & a bedroom. Of course they have their arguments, but what siblings dont?
My 10 year old, found his jealous streak when I fell PG with my 4th baby, he was 6 at the time, and refused to talk to me for days. He soon came round tho.