I used the Photoshop CS3 Smart blur as detailed in a www.russellbrown.com tutorial.

Use the lowest radius that yields good results, then push up the threshold slider.
Follow up with by brightening the white level with a levels adjustment.

forum discussion: http://forums.dpreview.com/forums/read.asp?forum=1006&message=29508232

original image by w333: http://img525.imageshack.us/img525/8014/33734607td2.png