M.F.
Ours were 22 months apart. A week or so before we had our second, I took my daughter up to the hospital to walk around, look at the babies in the nursery window, locate snack machines, have a snack in the cafeteria, etc. I let her know that was where mommy would go when the baby came.
Once he was born, we made sure she got to hold him and bring him a gift. We had the baby give her something too. It was Easter weekend, so she got Easter goodies from him. I also made sure that when she came to visit at the hospital that the baby was in the little bassinet instead of me holding him, and we let her crawl up on the bed with me for a little visit first.
As far as jealousy, my daughter never really had anything against the baby, but her behavior was more reflective of having to share mommy and daddy, and having less one-on-one time with me. We involved her as much as possible with the baby -- she'd get diapers for us, help pat his back to burp him, pick outfits, choose toys to show him, push the wheeled bassinet around the living room, etc.
You should be intentional about one-on-one time with him, but balance it with times together with the baby. There are probably some books you can get about new babies, etc.
Just remember that this is a big adjustment for him and as with anything, it will just take time. At the end of the baby's first year you'll look back and think, "man, that was a rough year!" The grace of it is that you don't realize how tough it is until you're done with it :-).
Make sure you have a good stash of appropriate DVDs and you know when his favorite shows are on TV. There really will be times that you need him to veg out and give you a break. My daughter watched more TV/videos that first year of my son's life than she has her whole 6 years combined!
Having your older son in a mother's day out or similar situation (even a weekly swap with a friend) will help tremendously. He'll get to be "big" and those MDO or swap days could very well be the only days of the week you do a load of laundry, cook a meal, or wash your hair for a while!
As far as nap schedule, you should remember that the baby's schedule won't be terribly predictible for the first 12 weeks. Just be sure you keep the older boy as close to his routine as possible, even if it means the baby has to be put on "hold" every once in a while. There were times where I had to make a decision about who to tend to in a heated moment (hungry infant and melting toddler). The fact is, the baby can wait 2 more minutes to eat (even if he's screaming), and he won't go anywhere while he waits. The toddler will continue spiraling out of control if you don't tend to him quickly.
Once the baby starts eating and sleeping at more regular intervals, you should be able to get one of his naps to match up or overlap with your toddler's afternoon nap. You will basically put them down at the same time, even if one doesn't fall asleep immediately. The goal is that they're both in their beds or rooms for about the same amount of time. Even after my daughter dropped her morning nap, we still gave her a morning "quiet time" in her room during the baby's mornig nap, and then they both napped at the same time in the afternoon, with about a half hour difference in wake-up times.
We actually did move both of ours to a "big kid" bed at 17 months. Our daughter got moved at that age because our son was on his way. Our son was moved at that age because I caught him one morning trying to get his leg over the top of the crib railing. It was an extremely easy move both times. In fact, we have several friends with kids close in age (18 mo to 2 yrs apart) who made the move at 17 or 18 months and no one had any problems. Our friends who waited until 2 yrs old had the most drama with the change :-).
Hope all this helps. Good luck!