I think that when reading The Lovely Bones, the first connection I made was with Laurie Halse Anderson's Speak. It is a story about a young girl who was raped at a party and called the cops who came and broke the party up. None of her peers knew why she called the cops, so they all started to hate her. It's all about how she dealt with the pressure, the hate, and her own demons after the rape. I think it would be interesting to compare it to Salmon's experience of dealing with her rape and murder in the afterlife as well as her family's experience in dealing with the loss of their daughter. There's a lot to be said for the emotional growth process of coping and learning how to live with yourself after such a traumatic ordeal - and how the victim is never the only one affected.
Let's not stop there. What about classic literature. In the William Shakespeare play Hamlet, the ghost of King Hamlet informs his son of the dastardly murder committed at the hands of Claudius. This idea of ghostly spirits seeking justice is a common one in many pieces of literature. By the way, don't forget the movie with Demi Moore and Patrick Swayzee.
Oh my gosh, yes, yes, YES! I absolutely adore the book (as well as the movie), and I'll admit that the entire time I was thinking of What Dreams May Come. Both of them have to do with different ideas regarding the afterlife and, more significantly, heaven.
I spent most of my time comparing Susie's heaven with the main character of What Dreams May Come. Susie's heaven, of course, contains a sort of ethereal vision of her wishes where she can "see" other people in their heavens, but may not interact with them (except for her couple of mentors). Eventually, she meets other Harvey victims in her heaven. In What Dreams May Come, Chris' heaven is a beautiful compilation of paints, colors, and nature (and yet it does not contain his wife, his main source of happiness). Different than Susie, Chris attempts to bring his wife to heaven. Chris' wife is in hell because of her suicide. In the visions of hell and wife-retrieval, What Dreams May Come alludes to Dante's Inferno.
Thus, these two novels (and subsequent movies) would make for a fabulous comparison essay! I hope these thoughts helped you a bit! Good luck!
There are a few novels that I can recommend that have similar situations to this one, a kind of magical realism. One is entitled The Five People you Meet In Heaven. It is about a man named Eddie who dies in a freak accident. Eddie wakes up in heaven where he encounters five people who have affected his life, whether he realized at the time or not.
Another novel that is somewhat related might be The Time Traveler's Wife. It is a love story about a man with a disease that causes him to travel in time, but he cannot control his travel. His wife is an artist who is forced to deal with his frequent absences and dangerous experiences. The author wrote this novel as a metaphor for her failed relationships, and The Lovely Bones is a novel that focuses on relationships, many of which fail, although it is because of the tragedy of Susie's murder. In Time Traveler's Wife, time travel is the vehicle that explores miscommunication and estrangement in relationships, the same as in The Lovely Bones.
In the Harry Potter series, there are several characters that interact with humans from the spirit world. There is one character called Moaning Myrtle who was ordered killed by Tom Riddle. Myrtle is now a ghost who haunts the second floor girls' bathroom at Hogwarts and she helps Harry and his friends from time to time. She tells Harry and his friends her story, so they know how she has been killed.
C.S. Lewis wrote a fantasy entitled The Great Divorce which is about a bunch of people that get on a bus in a dreary city. They soon learn they are all ghosts and the bus is going to heaven. When they get to heaven, they see all sorts of people they knew on earth and they learn various things from the people. This work is an allegory, but it does have an earth to heaven connection.
Finally, there is the Bible. The Bible contains many stories of earth to heaven connections: Adam and Eve talking to God in the Garden of Eden, Moses talking to God on the mountain, in the burning bush, etc., Jacob wrestling with God, Angels appearing to people such as Abraham and the three wise men, etc., etc., etc. - it's kind of an age-old theme.
Perhaps others can remember some other similar books.