The stories are based in part on the work of Spirit Communicator Mary Ann Wintkowski
The pilot shows a California license plate on a vehicle. Subsequent episodes show New York license plates
The town square is actually on the back lot of Universal Studios and there is a reason that it looks familiar. It is the same one used in the movie, Back to the Future (1985).
The show is filmed entirely on the Universal Studios back lot in Hollywood. In fact, the town square is the same one used in the Back to the Future movies, but modified to represent the fictional town of Grandview (i.e. the famous clock tower has been removed/hidden).
Jennifer Love Hewitt produced some of the episodes.
The show was alluded to in the cartoon Family Guy
Director John Gray is from Bay Ridge, Brooklyn originally and in many of the episodes there are references to streets and locations from Bay Ridge Brooklyn (Ex. Lento's Restaurant in the movie was the name of an actual Bay Ridge restaurant for over 30 years).
World renowned psychic James Van Praagh served as a consultant during some shows in the 2nd season.
'Ceasar Millan', also known as the "Dog Whisperer", has been featured twice in the Ghost Whisperer series. In the episode "Dead Man's Ridge" in season 1, Andrea's character was seen twice reading a book written by the Dog Whisperer, Ceasar Millan. Also, in the season 2 episode "Children of Ghosts", Ceasar Millan himself makes a cameo appearance in a small scene in which Delia brings her dog, Bob, to the Dog Whisperer to find out why he behaves so strangely at times (while the audience is aware that Bob behaves strangely because there is a ghost dog nearby).