This isn't all that difficult, so I hope the following helps:
1. assuming you are processing from RAW files, ensure that your conversion uses the same settings for each image so that the static parts of the image look the same in each image;
2. open all the images in PS;
3. select one image and then drag it into one of the other images (hold the shift key when you do so to ensure that the images are aligned);
4. repeat for the other images, by selecting and dragging them into the same base image;
That will give you one image with a stack of layers, where all the images are in perfect register.
5. Apply a hide all mask to each layer and then paint in with white in the mask to reveal the parts of each image that you want to show.
As an example of how this turns out, the following link will take you to an image I made using this technique during Easter this year (I was on a health kick at the time):
http://peterstacey.com/blog/wp-content/upl..._Day6_small.jpgRegards,
Peter