Image resizing

I would like to know what is the best way to enlarge in CS3.
I have Scott Kelby's photoshop book and it tells me to unclick "resampling" in IMAGE SIZE and then choose my size.
How does this work i have never really printed beyond 11x14,but woud like to.

Also,i have a 20d and would like to know the biggest i can go print wise with this camera and still get good qaulity prints.

Thanks

There is just no "one size fits all" answer on how large you can go. It is dependant on your image, how sharp is the original, how much noise is already there. I have printed as large as 30x40 off of a 20D file and the image was great at normal viewing distance. If you want to get up close to it and use a magnifying glass you will find issues. A print of this size will normally be viewed at 4 or 5 feet or more.

When I am working image to go to printing my normal process is to set the size in the crop options and then crop to the size I want and then sharpen to taste. If once I crop the image it is not what I want I will run Genuine Fractals against the original to see if it is any better than using the crop tool.

For an 11x14, assuming it is good to start with, you should be able to just use the crop tool. I would set the settings shown below.

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Have a read of my printing FAQ, it's in my sig.

It depends on what your output process is. From what I understand if you are printing to an Epson printer the optimal ppi range is between 180 and 360. So if you have an image at 300ppi you can lower the ppi to 180, therefore increasing the print size without sacrificing that much image quality.

If you don want to do a straight upsize however, resampling bicubic smoother followed by sharpening is supposedly the best method. I haven't done much comparing myself though. There are also 3rd party programs such as Genuine Fractals and Blow Up.

Depends what you're shooting, too...