Contrast Blending Actions
The Contrast Blending Actions stack and mask differently exposed images in order to combine the correctly exposed parts of all images in the result. The result can be visually controlled by adjusting layer opacity as well as by editing the masks.
The action set is available from Erik Krause
This is a semi automatic and slightly enhanced version of the techniques described on http://www.luminous-landscape.com/tutorials/digital-blending.shtml
See Contrast Blending for a collection of some other techniques.