As anyone who's seen Episode VI: Return of the Jedi knows, there's a scene, after the Rebel Commando team has been accepted into the Ewok tribe, between Luke and Leia where some very intriguing familial topics are discussed. Luke reveals his parentage, but more importantly (at least to this entry) he tries to talk to Leia about his mother. Emphasis on tries.

Luke
Leia...do you remember your mother? Your real mother?

Leia
Just a bit. She died when I was very young.

Luke
What do you remember?

Leia
Just...images, really. Feelings.

Luke
Tell me.

Leia [a little surprised at his insistence]
She was very beautiful. Kind but...[looks up]...sad. Why are you asking me this?

Luke
I have no memory of my mother. I never knew her.

Now, for a long time, the fan base assumed Leia was referring to Padme in that scene. Having seen Revenge of the Sith, I now believe this to be a fundamentally flawed assumption. Bear with me here.

First, one must remember that Luke has yet to reveal that he is, in fact, Leia's brother when this scene begins. Is Luke asking Leia about his own mother? Or is he simply trying to find out what it feels like to have had a mother at one time? I'm thinking, now, that's it's probably the latter.

Second, Bail Organa was married to the Queen of Alderaan, whom we, the audience, see him deliver Leia to at the end of Revenge of the Sith. Is it she that Leia is remembering? Could she have died soon after she adopted Leia, and could Bail, then, have been remarried? It seems likely. In all of the sources set between Episodes III and IV where we see either Bail Organa or Princess Leia, the Queen of Alderaan is nowhere to be seen. Not in The Paradise Snare, not in The Princess Leia Diaries (Infinities, I know, and also a source that insinuates that Leia is, in fact, remembering Padme, not the Queen of Alderaan), or most importantly the Episode IV Radio Drama. In fact, in that last source, Leia is now the Senator of Alderaan and Bail is the Viceroy of Alderaan. I know that an absense of evidence is not evidence at all, but this all seems to point to the Queen of Alderaan being dead well before Alderaan is destroyed. In fact, in Republic # 61 (written by John Ostrander and set more than a year and a half before Leia is born), Bail mentions that he and his wife's latest attempt at concieving a child "nearly killed her." Could the Queen of Alderaan be physically weak, or sickly? She seems healthy enough in the film, but who can say? This is also assuming that Leia believes Bail Organa and his wife to be her real parents (at least until Luke delivers his revelation), something that could not be assumed until the final prequel had been released. Are there any EU sources out there that contradict this, or state outright that leia knew all along that she had been adopted?

Third, in the latest film, infant Leia certainly doesn't seem to have any sort of connection with her dying mother; no shared moment at least and certainly not any more of one than her twin brother would have had.

I've just begun reading the Black Fleet Crisis. It's a trilogy of books written by Michael Kube-McDowell set some 12 years after the Battle of Endor, and one I've never read. So far, Luke seems a tad out of character, and quite a bit out of touch with humanity. When Akanah, a woman claiming Luke's mother is, in fact, named Nashira and still alive, Luke says he needs to run all of this new information by Leia because:

"If you'd said, 'No, this has to be our secret,' I would've doubted you. But there's anothe reason I have to do this. I have no memories of my mother. Leia has but a few, no more than glimpses touched by emotion."

Now, this heavily implies that Luke was talking about Padme during that conversation on Endor's moon. So far, having gotten only a bit beyond this section of the book, this hasn't at all been expanded upon. Is Luke being a bonehead? What's going on here? Had he never bothered to actually expand on what he was trying to get at when he talked to Leia all those years ago? It seems like the only likely explanation, but it's not one I like all that much. If anyone else has any ideas on this, please drop me a note. When Luke goes to Leia and Han's apartment, he asks Leia for permission to mind-scan her (or something along those lines) for information on their mother (now that he has something to go on) but she refuses (avoiding more continuity trouble, thank heavens). He then leaves to search out the White Current (of which his "mother" is a member). More as this develops.

Edit: Found it. On pg. 117 of the ROTJ novelization, it states that Leia indeed thought of Bail and his wife as her adoptive parents. It goes on to mention, though, that Leia remembers images of a woman running and hiding in a trunk. So...I think this evidence is questionable, at best (especially in light of a number of other things found in the novelization).