This just in:

Well, probably not White Oleander...

Does she want "I was a bad mother but I got better" movies? Or "I had a bad mother but I survived and I'm OK" movies? or "Here's an exemplary [but not impossibly ideal] mother" movies?

I'm not being flippant, I'm just trying to figure out what would bring "encouragement, reconciliation, and hope" to incarcerated women.

Redemptive? Hmm... I guess I shouldn't recommend Mommy Dearest...

OK, we're not helping. How about:
Pieces of April
Little Miss Sunshine (problematic though it may be)
Mermaids
Housekeeping
What's Eating Gilbert Grape
A Raisin in the Sun
The Joy Luck Club
Ray
Antwone Fisher

How about Boyz n The Hood, Akeelah and the Bee, or October Sky?

Women, specifically? I'll have to give that some thought.

Otherwise...
Parenthood (Sure, it's chintzy in places, hopelessly bourgeious, and RonHowardy, but I still think it has a lot of merit--and good examples along with bad ["I love you so I want to give you what you want"].)
Boyz in the Hood (perhaps not a great film for prisoners...)
Braveheart

I'm sure I'll think of others.

Link to our thread on "Fathers on film"
Link to our thread on male role models
Link to our thread on female role models

Shakespeare Behind Bars--documentary about a production of The Tempest in a men's prison, but focuses specifically on the play's theme of forgiveness and reconciliation, on the parent/child relationship (Prospero & Miranda), and many other relevant issues.

I'll Be Seeing You - rare Christmas oldie starring Ginger Rogers, Joseph Cotten, and a teenaged Shirley Temple. Plot centers around a woman on prison furlough, meeting a shaken serviceman from the WWII, and how they fall in love, and how she discovers that she could be normal again.

Remember the Night - another rare Christmas weepie, scripted by Preston Sturges, about a kleptomaniac spending the holidays with the prosecutor out to put her away. The first film of Fred MacMurray and Barbara Stanwyck.

Hoop Dreams - not the most feminine of movies, but it's one of the most engrossing docs ever filmed, and the scene when the mother gets a nurse's degree is one of the most thrilling scenes in a film--change IS possible, no matter how stark the circumstances.

I second _Boyz in the Hood_. _Akeela and the Bee_ makes an interesting double feature.

Unseen by me, but may be interesting, maybe not:
Tacones lejanos (aka High Heels) (1991) by Pedro Almodovar--a mother returns from prison after 15 years, to find that her daughter married one of her prior lovers.

Stranger Inside (2001) TV-movie on DVD

Getting Out (1994) TV-movie on VHS

Chinjeolhan geumjassi (2005) -- only tangentially applicable, but supposedly a kick-butt action film from South Korea. ETA: English Title: Lady Vengeance... and a third part of a trilogy, which included _OldBoy_. Hmm....

It's not out yet, but Bella has some important things to say about, shall we say, parenting-related matters.