This is a roster of all known and confirmed Astromech Droids in the Saga. No names have been invented.

The Phantom Menace
R2-A6: Ric Olié's Droid #
R2-B1: Blue / gold in Royal Starship #
R2-C4: Orange / Yellow in Theed Hangar #
R2-M5: Red in Theed Hangar #
R2-R9: Red in Royal Starship #
R2-T0: Owned by Watto #
R5-X2: In Jabba's box in the Boonta Race
G8-R3: Oddly named Arfive Unit in Royal Starship

Attack of the Clones
R5-D4: Mos Espa #
R3-T7: Yellow on Coruscant streets in Uscru District #
R4-A22: Orange near Dex' Diner #
R4-P17: In Obi-Wan's Starfighter #

Revenge of the Sith
R4-G9: Accompanies Obi-Wan to Utapau #
R4-P44: Green, assigned to the Vigilance
R4-F5: Used by Plo Koon in his Delta7 Interceptor #

A New Hope
R1-G4: At Jawa Auction #
R2-A5: Green / white in Mos Eisley
R2-Q2: In Tantive IV & Biggs' Droid #
R2-X2: Black / white at Yavin 4 & Theron Nett's Droid #
R3-T2: Red / white in Mos Eisley #
R3-T6: Blue / Red in Death Star #
R4-E1: Bo Shek's Droid seen in Mos Eisley #
R4-I9: Death Star I #
R4-M9: In Tantive IV #
R5-A2: Yellow on Mos Eisley
R5-D4: Jawa Auction #
R5-D8: Jek Porkins' Droid

The Empire Strikes Back
R3-A2: Orange in Echo Base #
R3-Y2: Green in Echo Base #
R5-M2: Shawn Valdez' Droid in Echo Base

Return of the Jedi:
R2-Q5: Death Star II #
R5-J2: Name has been shown on the figure's card.

R4-5K: Vader's Astromech. Appears on Hasbro lists. Movie unknown & not confirmed until proven by Hasbro

Star Tours:
R2-D7: With Arfour head ... (Japan)
R3-A2: Same one as seen on Hoth (US)
R3-D3: (US) #
R4-M9 #
R5-D2: Get repaired by G2-9T #

Thx to: http://www.swstartours.net/aspbite/categories/index.asp?tim=8:37:57%20PM

# Made by Hasbro