Bail Organa's diplomatic Corellian Corvette (CR90) was originally known as the Star of Alderaan. The 150 meter long vessel was called Tantive IV in honor of representatives of the Tantive System afterwards.

I've added the characters that appear aboard the Tantive IV during the movies.

REVENGE OF THE SITH
Alderaanian Crew:
Bail Organa
Sateen Vestswe (*)
Sheltay Retrac
Captain Jeremoch Colton
Captain Raymus Antilles
Corla Metonae
Unknown Crew Members
Unknown copilot of Tantive IV
Unknown Alderaanian standing between Kenobi and Organa (*)

Others:
Obi-Wan Kenobi
Yoda
- Artoo Detoo
- See Threepio

A NEW HOPE
Alderaanian Crew:
Princess Leia Organa
Captain Raymus Antilles
Lieutenant Pello Scrambas
Ensign Chad Hilse
Unknown Alderaan Fleet Troopers
Unknown Alderaan Fleet Troopers 2
Unknown Alderaan Fleet Troopers 3
U-3PO: left
Artoo Detoo
See Threepio

Imperial:
Darth Vader
Commander Daine Jir: Has an insignia of a Lieutenant, but holds the rank of commander.
Commander Praji
R4-M9: Imperial Droid stationed at Devastator
R2-Q2: Formerly part of an Imperial Reconnaissance fleet. Appears as well as Biggs' copilot
Stormtroopers

(*) Deleted Scenes