After cropping a file from Canon 1DsMkII, converted from RAW using ARC 3.2, and resample check box uncheck, I often end up with PPI that contain fractions and that are not the usual 240, 360 etc. For instance, I might end up PS CS2 calculating a PPI of "302.575" after adjusting the image size under the Image/Image Size dialogue box.
Should I instead type in the PPI and let PS CS calculate the image size? Does the way I currently doing it compromise my output quality? (Usually printed to my Epson 2200).
There is something to be said for arriving at the final output resolution in Photoshop rather than making your printer driver do it, as PS is likely to do a better job with whatever up- or downsampling is required.
Set your output resolution (I print via ImagePrint so I use 360ppi) and then check the "constrain proportions" (assuming you want the resized image proportions the same) and "Resample Image" checkboxes. Select "Bicubic Sharper" if you are downsampling. Then enter one of the dimensions for final print size; PS will calculate the other dimension, maintaining the image's proportions, and resize and resample to final output size and resolution. These parameters determine your final file size.
Others here will no doubt point out other options. Give this a try.