Congratulations! Just want to say first of all that having two is completely wonderful
and also, of course, completely knackering!
All I want to add is not to be worried by your dd being sad about ds being born. It is a natural feeling for them to have and she WILL get over it. The best thing you can do for her is keep her routine as normal as absolutely possible. That way she will figure out quite quickly that her life hasn't actually changed as much as she thought it had. Also, expect some possible babyish phases from her and don't be too hard on her for it.
I would also second redstripyelephant to get her involved as much as possible but don't be worried if she doesn't want to. My dd was 20months when ds was born and, if I'm honest, she pretty much ignored him for the first 6 months! We did worry a little about whether she would ever accept him but then, suddenly, it stopped being an issue. They now (at 2.11 and 15months) are competely gorgeous together and if for any reason they are not together she asks for him constantly and he yells her name at the top of his voice!
I also agree with mackerel - validating their feelings is really important. So if, for example, she says she doesn't love ds, try not to say 'but of course you love your brother'. The best thing you can do there is to agree with her in a way by saying something like 'i know sweetheart, he is very loud when he cries, isn't he?'. Don't worry, you won't be encouraging her to hate him, it will just allow her to verbalise her feelings and feel understood. It's a bit of a way off for you yet, but Siblings Without Rivalry is a great book to have. Ignore the annoying American way it's written but the messages are very interesting.
Sounds like you're already very sensitive to your dd so I'm sure everything will be fine. But don't forget, even if things are difficult while he's a little baby, very quickly she will never be able to remember a time without him. Dd was looking at her first birthday photos the other day and was very cross that her brother wasn't in any of the photos!