Can i combine 3 images to increase contrast ratio

Anyone know any easy or not so easy techniques to combine 3 different exposed images together, while retain good information out of each image.
Combining image like this will then have all detail in highlights, good exposure in mid tones, then all detail in shadow areas.

Also has anyone come across any situations where photographing like this could be useful?

thanx heaps

(If anyones interested I have technique to combine over and under exposed images)

well...ive never done this before but im sure it includes curves, channels or masking of some kind.

If you get a chance....go to a book store and pick up "Photoshop Master Class" by John Paul Caponigro. It has a chapter called "extending dynamic range" that talks just about this (scanning images and combining).