Are there any references to spirit of ancestors in Buddhist folklore? As seen in some movies, communication with spirits is shown. Is this practical ? What is the Buddhist view on spirits?
"Spirits" are lower ranking devas that occupy the realm of the Four Great Kings, and include earthbound devas too, that live invisibly in human cities and influence human beings telepathically. These correspond to the nature spirits found in all traditions. I cant think of any examples of spirits of ancestors as such, but King Bimbisara appears to the Buddha as a king in the realm of the Four Great Kings after the former's decease.
There is actually an English version of the Peta-Vatthu, but since it does not gives any references of its origin and certain other shares are not very in the frame of the original giver, you should be aware that it could be actually not really given, put simply pirated like it is very usual today. So beware of do not becoming a hungry ghost in this realm, a therm that is very proper for may kinds of existences here in this world, on googlyana: Offerings for hungry ghosts in Googleyana
(Note: this answer has not been given with the agreement to be means of trade or the purpose of trade and keep people trapped and bound. How you handle it lies in your sphere, but does not excuse the deed here either.)
Not exactly, there are stories where relatives want to find out where a recently deceased loved one was reborn. However no communication happens between them, the Buddha just states, they were reborn here, because of X.
Communication with deities is sometimes mentioned, but spirits or ghosts, not so much in my knowledge.