DPI is the acronym for dots per inch. This is a term that refers to printing and means that there are "x" number of dots per square inch of the printed image. 300 DPI or PPI (used interchangeably) is the print industry standard for printed images. Since DPI is only relevant to printed images, cameras do not have corresponding settings. However, there are a number of factors that need to be in place on a camera to print at this high quality.
Use a camera that has a high pixel count. The pixel count is generally measured in megapixels and range from 1 to 18 megapixels (as of 2010). Printing larger images at 300 DPI is possible with higher megapixel counts. For example, a 3 megapixel camera's largest print at 300 DPI is 6.5 by 4.8 inches compared to 8.1 by 6.1 inches on a 5 megapixel camera.
Choose a camera with a large light sensor. The bigger the light sensor, the more information it captures.
Set the camera to the highest resolution settings possible. On professional cameras, the "RAW" setting captures the most data in an uncompressed form. On point-and-shoot or other cameras without "RAW" settings, set the resolution to the highest JPEG quality possible.
Use as low of an ISO as possible for the lighting conditions. Higher ISO settings create grainy images with less usable pixel information.