Make a single polaroid in with a white background and black rectangle. Bevel to make it look more like a real polaroid.
Now copy that polaroid onto a new canvas and duplicate until you have enough to make a collage. Rotate the polaroids and arrange them in a collage you like. Remember not to leave huge gaps between them, or you might be missing important parts of your finished photo.
Now you need to merge the polaroids. Select all of the polaroid layers (Ctrl+click). Then (Right Click – Merge Layers). Using your selection tools, select all of the black portions of the polaroids where the photo will go. Hold CTRL between each click to add to your selection.
Make a new layer by cutting from the original (Shift+Ctrl+J).
Now, add you picture above the black portions layer.
Select your picture layer and clip it to the black portions (Ctrl+G). You can now resize and move your image until you are happy with where it sits in the clipped mask.
I changed the color of the background on mine and ta-da. Polaroid Collage from a single picture.





