I'm a Photoshop novice.

I'm trying to duplicate the effect of using a composite track in V8, set to "Screen" mode, with a feathered mask to limit the area of the effect on the lower track. (I'm lightening up some areas in shadow on a photograph)

How do I do this easily in PS? (I'm sure it's easy...as far as "easy" applies to PS CS3).

thanks.