. . . you might try:

Between Friends by Debbie Macomber FIC MAC
Growing up in the Post-World War II Era, Jillian and Lesley develop a close friendship, which continues, even as their lives pull them in opposite directions.

The Book Club by Mary Alice Monroe FIC MON
On the surface, it is a monthly book club, but for a group of women it is a chance to share their hopes and fears and triumphs.

The Boy Next Door by Meg Cabot FIC CAB
A series of emails relate how gossip columnist Melissa Fuller trades in her shallow life when her elderly neighbor is attacked.

A Celibate Season by Carol Shields FIC SHI
Faced with a job-related 10-month separation, a couple chooses to maintain contact through letters. As the months progress, the couple's letters grow less frequent and more revealing--and their "season of celibacy" becomes more of a challenge than either Jocelyn or Charles had imagined.

The Color Purple by Alice Walker FIC WAL
In the 1920s two sisters, one a missionary in Africa and the other a child-wife in the Southern United States, find support through letters to each other and God.

Fair and Tender Ladies by Lee Smith FIC SMI
Growing up in the Pre-World War I Virginia Appalachians, Ivy dreams of becoming a writer. Poverty and early pregnancy waylay her professional plans, but her letter writing never ceases.

The Letters by Luanne Rice FIC RIC
A series of letters reveals the evolution of one couple's relationship as they fall in love, confront the loss of an adult child, and struggle to rediscover what they mean to each other.

The Love Letter by Cathleen Schine FIC SCH
An anonymous love letter arrives in Helen MacFarquhar's mail one summer morning. Written by an unknown lover to a mysterious beloved, the letter becomes Helen's obsession.

Ready to Fall by Claire Cook FIC COO
A witty tale of marriage and midlife longing, as a taken-for-granted wife pursues a fantasy love via e-mail.

Sam’s Letters to Jennifer by James Patterson FIC PAT
Author Jennifer returns to the resort town where she grew up to help a beloved relative. In letters that Jennifer finds, it is revealed that her relative has held a secret for decades.

The Secret History of the Pink Carnation by Lauren Willig FIC WIL
The French eventually unmasked the Scarlet Pimpernel and the Purple Gentian, famed spies in the Napoleonic wars, but as Harvard graduate student Eloise Kelly discovers at the start of this breezy historical romance, the identity of the Pink Carnation remains a mystery.

The True and Outstanding Adventures of the Hunt Sisters by Elisabeth Robinson FIC ROB
While working on her suicide letter, Olivia receives news that her sister, Maddie, has leukemia. Even as her illness progresses, Maddie remains hopeful, challenging Olivia to pursue her dreams.

The Wednesday Letters by Jason F. Wright FIC WRI
After their parents’ death, three grown children discover boxes of letters written by their father to their mother each Wednesday of their life together, revealing shocking secrets of their past.

A Woman of Independent Means by Elizabeth Forsythe Hailey FIC HAI
The story of Bess’s life, from a Texas town at the turn of the 20th Century to the turbulence of the late 1960s.

The Woman Who Knew Gandhi by Keith Heller FIC HEL
Based on an aside in Mahatma Gandhi's autobiography this novel boldly imagines a long correspondence between a spiritual leader from the East and an ordinary woman from the West.