Some things are easier, some things are harder. You don't tend to stress as much with #2 (I forgot about tummy time until DS was rolling himself over

). WHen #2 is past the sleep-most-of-the-time stage, they can amuse each other, giving you a chance to get other stuff done (with just one, I would stress about leaving her alone).
DD was 23 months old when DS was born, and never really displayed any serious jealousy. I tried to get her to help as much as possible - if she could help look after him, then she was quite happy. She corrected anyone who said it was *Mummy's baby* - he was *her* baby. She did figure out she could get away with things while I was occupied feeding DS, but didn't push it too far, and I just tried to be prepared with things to keep her busy.
As far as the early days go, just take each day as it comes, and don't put too much pressure on yourself to go out with two children before you're ready. Try to keep your first ventures out limited - one stop, not too long out, etc, until you're feeling confident. I found it only deteriorated into a complete nightmare when I tried to get them both in and out of the car several times in one outing.
Yes, things will be different. Yes, sometimes you will probably wonder whose stupid idea this was. Just try not to expect too much from yourself or your babies - take it slow and give yourself time to settle into it. And, as always with a new baby, if you get showered and dressed before 4pm, then it's a good day

All the best,
Karen
DD Tara 19.6.01
DS Xander 30.5.03