From Starwars.com :

Jake Lloyd: Anakin Skywalker, The Phantom Menace
The actor who portrayed young Anakin Skywalker in The Phantom Menace, Lloyd was cast at the age of seven-and-a-half, having been watched closely by casting director Robin Gurland since she first spotted him as a five-year-old.

Daniel Logan: Young Boba Fett, Attack of the Clones and Star Wars: The Clone Wars
Boba Fett spans the entire Star Wars saga, and started with the character as a young man, portrayed in Attack of the Clones by television and film actor Logan. Recently, Logan reprised this iconic role, voicing the character in Star Wars: The Clone Wars television series.

Matt Wood: General Grievous, Attack of the Clones, Revenge of the Sith, and Star Wars: The Clone Wars. Bib Fortuna, The Phantom Menace.
Wood, the Supervising Sound Editor for the Star Wars prequels, created the voice for General Grievous for Episode III, and voices for other prequel characters as well. Always busy with his technical responsibilities for the film, Wood managed to find his voice -- or rather helped the nefarious droid general find his voice.

Amy Allen: Aayla Secura, Attack of the Clones, Revenge of the Sith.
A striking blue Twi'lek Jedi on the cover of a Dark Horse comic made an impression on writer/director George Lucas. So much so, that he requested that a fit female extra be found to play the part. Allen, who was a production assistant at ILM, was recruited for Episode II, and returned to reprise her role in Episode III.

Caroline Blakiston: Mon Mothma, Return of the Jedi.
Blackiston's busy career began in the 1950s and has continued with dozens of television and film appearances in the U.K. and beyond.

Julian Glover: General Veers, The Empire Strikes Back.
The busy actor has appeared not only in The Empire Strikes Back and Indiana Jones and the Last Crusade, but also voiced Aragog in Harry Potter and the Chamber of Secrets, and played Triopas in Troy.

Frank Hensen: Stormtrooper, Rebel guard, Skiff guard, Return of the Jedi.
Hensen's filmography is as varied and interesting as his many roles in Episode VI. In addition to acting roles he has been a stunt coordinator and fight coordinator, appearing recently in Sherlock Holmes as a stunt performer.

Ian Liston: Wes Janson, The Empire Strikes Back.
Liston's character of Wes Janson has built a loyal following not only from his screen time, but also from the character's role in a number of Star Wars novels and comics. Liston's acting career spans several decades.

Jack McKenzie: Cal Alder, The Empire Strikes Back.
McKenzie, who played the deck Lieutenant on the Hoth Rebel Base, has appeared in a number of television series and movies, including the classics A Bridge Too Far and Gandhi.

Christopher Muncke: Captain Khurgee, A New Hope.
The movie and television actor played the scanning crew leader and pilot in the first Star Wars movie. As an added trivia note for fans, Muncke also appeared with fellow Star Wars actors Anthony Forrest and Garrick Hagon in the 1977 James Bond movie, The Spy Who Loved Me.

Chris Parsons: 4-LOM, K-3PO,The Empire Strikes Back.
In addition to performing two iconic droid characters in The Empire Strikes Back, Parsons also performed in Return of the Jedi.

Toby Philpott: Jabba Puppeteer, Return of the Jedi.
Philpott's puppeteer and animatronic credits include Labyrinth, The Dark Crystal, Little Shop of Horrors, and Who Framed Roger Rabbit, among many others

George Roubicek: Commander Praji, A New Hope.
This Austrian-born actor has had a storied acting career, spanning more than 50 years. Beginning in 1957 with The One That Got Away, Roubicek has performed agents, officers, soldiers, and kings.