What I do - 

1. Scan at 300 dpi
2. save using Windows Paint (this way you have more wiggle room when you edit the scans in Photoshop)
3. Edit in Photoshop
        A. For covers
	-straighten using the measure tool (on most covers, I either use the logo as my guideline, or the art edge, depending)
   	-crop
    	-use the clone stamp tool to remove any stains/discolorations/writing/color flaking (this step can take me up to 4 hours)
	You can use the "save as action" function for the next five steps (then all you will have to do is hit play on all successive pages)
	-Image/adjustments/brightness-contrast/+14 to brightness,+20 to contrast
   	-image/adjustments/hue-saturation/+14 to saturation
   	-image/adjustments/selective color/black - +100 to black
   	-image size/dpi to 150, width to 1152 pixels
   	-save at jpeg quality 4 or more (less than 4 and you will get image degradation)

       B. For interior B&W pages
	-straighten using the measure tool (I usually use the left edge as the guideline)
   	-crop
	-Image/adjustments/brightness-contrast/+18 to brightness,+60 to contrast
	-image/adjustments/selective color/black - +100 to black
	-use the paint brush tool to take out any creases or discolorations
	-image size/dpi to 150, width to 1152 pixels
   	-save at jpeg quality 4 or more (less than 4 and you will get image degradation)

Hope that helps ya out.

Cimm