Sure way to quantify Northern blots

[Jean-Francois Larrivee]

Does anyone have a sure way to quantify Northern blots? 

I'm having some trouble with the reproductibility of my results. I
used to use a chromoscan and scan my autoradiograms, but it's very
time consuming, not very effective and since I'm not the only one that
uses the chromoscan, it's always uncalibrated.

I plan to scan the autoradiograms on a computer scanner and then
analyse them with a dedicated software.

Are there any good PC-compatible software around to analyse these 
data?

Thanks a lot

Jean-Francois Larrivee