If you are leaving out of San Pedro, two suggestions would be the Doubletree and the Crown Plaza; both are very near the pier and offer free shuttles.
If you are going out of Long Beach, our member gdjoslin recommends the Coast Long Beach Hotel. He has some great photos of it here
. Just scroll down a ways.
Oops, I see you are cruising on Royal Caribbean, so you will be leaving out of San Pedro.
You should take a look at the photos anyway--they are fantastic!