Hi! I suspect the reason you've only gotten one reply is because those of us with two are too busy to answer!
Seriously, life with two is quite a juggling act. Mine are almost exactly 25 months apart, and the first couple months were . . . well, I guess I shouldn't sugar-coat this (you're not going to change your mind anyway right?) were pretty brutal. Until Ryan started sleeping through the night (at about 10 weeks), I was more tired than I think I've ever been in my life. There was little opportunity (as with the first baby) to "nap when the baby naps", unless I lucked out and got them both to sleep at the same time, which didn't happen very much until the baby was a few months old. Now that he's 7 months old and more on a schedule, it's quite a bit better, and I'm thinking that it will be even better by the time they're both down to one nap a day (of course, by then he'll also be walking, so that could present problems of its own). But I had (and still have) plenty of days where I didn't feel like I accomplished a whole heck of a lot and a few where I was pretty short in the patience department and felt like a candidate for worst mother of the year. Still I only had one day where I had to call my husband and make him come home early from work -- the baby had been crying for a solid two hours and I hadn't been keeping tabs on my older one until I caught a glimpse of her streaking past me without a stitch of clothing on, that's when I knew I needed to call in reinforcements!
My daughter rarely showed any problems with jealousy when the baby arrived (we had a couple times where she told me "Mommy, go lay Ryan down"), but she did have problems getting and staying asleep for the first time in her life. That too seems to have worked itself out (more or less -- and I find it doesn't affect me when she has a bad night because she goes to her daddy if she gets up in the middle of the night).
And as for two in diapers, that truly is no big deal (at least to me). I actually found that easier than the huge emotional and time investment potty training is seeming to take!
OK, so it I haven't totally scared you, let me just say that I am so thankful to have my sweet little boy in my life and cannot imagine what I would do without him! And I absolutely love watching my children interact. Ryan just obviously adores his big sister, and she is just a little mother hen to him. They are so, so sweet together. As hard as it is at times to coordinate two kids, I don't ever regret it (and I'm still contemplating whether we should have just one more -- oh, they're like salted peanuts! :7 ).
If you have family or friends nearby, don't be shy about asking for help! Try to get your older child involved with the baby -- we had a present waiting at the hospital for the baby to "give" to Lauren when she came to visit -- have him help you by getting diapers or burp clothes if he's interested, and make an effort to have lots of one-on-one time with him whenever possible so he doesn't feel lost in the shuffle.
Congratulations on your new arrival -- you will do fine, I'm sure!