How to Fake Cross Processing in Photoshop
To create a cross processing effect in Photoshop simply add a new adjustment layer by going to the menu bar and go
Layer / new adjustment layer / colour balance
Then click highlight radio button in the panel and move the slider full yellow and then click the shadows radio button and click all the way to green.
You can mess with the colour adjustments to get the effect you want. Red or magenta in the mid tones works well too.
Make a duplicate of the original and roughly mark out a wavy border with the polygon lasso. Feather to about 55 or more and then apply new colour adjustment to it.
Finally blur it slightly with Gaussian blur and you get a fake Cross processed image.