Depending on the size of the print, I would scan at about 300dpi with no unsharp masking on in the scanning software (I find they are always way to aggressive). Do your cropping and tonal adjustments (curves, midpoint, etc) then unsharp mask just enough to be able to pick the difference when either 'previewing' the effect, or jumping between the 'undo' command and 'redo' (depending on software being used). Resize the image to how ever many pixels you want (I change the dpi to 75 but in reality the screen dosn't care what that says). Aim for about 450-500 pixels high and/or 700-750 wide. People with high resolution screens will get to see a reasonable size pic, people with low resolution won't have to scroll too much (a big turn off when viewing pics online). Do another unsharp mask, watching that you don't introduce highlights that appear from over sharpening. I also expand the 'canvas' size by 1 or 2 pixels using black to give the picture a border to differentiate it from white/light backgrounds. Save the picture as a jpg, altering the quality to match your size/quality expectations. View the jpg in your browser, as you might be surprised how different (usually darker) the browser presents the pic (you really need to calibrate your image software to your browser, although everyone else will see something different anyway!. Post it to APUG and we can see your handiwork!