Cross processing is the process of developing Slide film in Color negative chemicals. Slide film is higher contrast than colour negative and the colours become strange because the film is supposed to be developed in a different way (E-6 slide film chemicals).
Below are some recently developed prints. The prints were all developed with the same settings which should have produced a regular color print. But because I am using a cross processed negative, the colours are shifted. This is not a bad thing however as this is the desired effect. You can reference what film I used by looking at the contact sheet samples below. All of the photos were developed with the same settings to keep consistency. If you look at the contact sheet samples below, you can see if the photos were taken at different times of the day or under different lighting conditions by their variation in colour.
If you are into Lomography or similar styles of photography, this is usually the process in which people use to make their images look more interesting. There are many Lomography books that are filled to the brim with cross processed shots.
Every brand of slide film which is cross-processed contains a distinctive look. I hope the guide below can help you choose what negative you would like to use.