peter carter , Oct 03, 2010; 09:29 a.m.
There is no substitute for a clean negative and a clean scanner. This will get rid of most dust spots and ultimately save you the most time. I use the Edwal Anti-Static Cleaner, but there are lots of cleaners out there. The anti-static part of the Edwal stuff gives it an upper edge.
For what is left, I use the AKVIS retoucher. http://akvis.com/en/retoucher/index.php . Although it was made for restoring photos, I can use the multi-select tool in PS to identify all the spots at once. There is also a stand-alone version of this product and it also works in PSE. There is a download trial available.
But seriously with silver based film, there is no real auto widget that will do an acceptable job. I would have one otherwise. ;)