Who is Luke Skywalker's and Princess Leia's mother?

Queen Amidala, I believe. So says the BBC's bluffer's guide to Star Wars, anyway:

http://news.bbc.co.uk/1/hi/entertainment/342351.stm

Hmm... Well, after I watched all the Star Wars movies, I remember their mother being Padme, assistant of Queen Amidala in The Phantom Menace, and Ambassador of Naboo in the other two movies.

Padme
https://en.wikipedia.org/wiki/Star_Wars

Born Padmé Naberrie, Queen Amidala was the formal name of the royal leader of Naboo.

When in danger, Queen Amidala disguised herself as one of her handmaidens, and adopted her less formal name of Padmé.

When her terms ended, Amidala was constitutionally obligated to step down as Queen... At the request of the new Naboo monarch, Queen Jamillia, Amidala served as Senator of Naboo, taking the position once occupied by Palpatine.

Before slipping away, Padmé remained strong enough to give birth. In the strange alien facility of Anakin's nightmares, she gave birth to twins -- Leia and Luke Skywalker. Obi-Wan Kenobi, Yoda, and Bail Organa vowed to keep the children safe.

http://www.starwars.com/databank/character/amidala/