Our kids are 21 months apart.
Our son desperately wanted a big Buzz Lightyear when his sister was born. We purchased one, didn't tell him, and surprised him when he came to the hospital to meet his little sister (this was 2 years ago before the H1N1 scare).
We also made sure to have things at the hospital that he may find interesting (colored pencils, stickers, notebook). He was more interested in the snack station and the cookie warmer. The nurses absolutely adored him, and he soaked-up the attention. We also took lots of pictures and let him "hold" his new sister with our assistance.
My best advice from day 1: set aside special time one-on-one with him and you, him and daddy so he doesn't feel like all the attention has been shifted to his little brother.
I'd also give him simple "jobs" that he can help you with during the day so he feels important. Getting diapers/wipes, helping pick clothes for his brother, helping push a stroller, etc.
Luckily, you will find that with such a short age difference, the adaptation required isn't too tough - at least that was our experience.
And, we're fortunate that they're best friends......gets a little creepy when our son says he wants to marry his sister, but he's not quite 4 yet and still doesn't quite "get" it.
Good luck!