About neg scanning:
i went through the ColorNeg pages following the link suggested here above, moreover i downloaded the plugin as well.
It is interesting, the guy is a bit arrognt by saying nobody else does it correctly but he does have a point here and there.
The plugin also seems to work quite okay, although it does not give those easy-and-perfect positives from the colour negative, as he says that in majority of cases it should. It is definitely easier though, than messing around in Photoshop with different channels to get to an acceptable positive.
He does have problems with the concept of color management and color spaces, though. He suggests to just scan and "assign your favorite color space" to the image, which is a total bullocks, since scanning gives an image in a certain color space and if you don't use that, it's a mess from the start and it can never be correct.
SO actually you have to make sure to scan into adobe rgb and work in that (it's the only color space his plug-in correctly handles, and he forgets to say this clearly) OR scan to any color space and CONVERT to adobe rgb (but not ASSIGN as he suggests - assigning a different color space breaks the image immediately).
So,with some precautions, the plugin might actually help handling C41 scans.