need cropping advice

I know there are other posts/threads on this subject but they didnt answer the question I have about cropping..

I want to crop an image to a certain ratio (4x6 & 8x10). What is the best way to do this? Should I go into Photoshop and use the 'front image' way (gives the pixelxpixel amount) and from what I have read crops and basically adds empty pixels to keep the image the same size. Or should I input 4inx6in and crop that way? or is there another way which would be better? I want the highest quality possible for printing. Thanks

I've been using ACR in CS3. The crop tool works great and just as you indicated, it crops by ratio.

Up till now I've been using the crop tool in CS2/CS3. It allows you to set the crop and the resolution.

in DPP there is a crop tool that can crop by ratio or freely. [Choose Tools> Trimming].