I agree with Larwick; the pixelly aspect comes out very well. I'll add: The usual issues with transferring images from screen to print applies (not all of the colors you have on screen are printable.). In practice, this mainly means you need to check for very saturated colors and do some fiddling with curves to get a result close to what you want.
If you can get an ICC profile for the printer, GIMP has a 'color proof' display filter that can give you an approximate idea of what your image will look like printed. For example, with some recent print work, I found that a bright yellow sun printed out as mid-green. (this looks pretty weird

. The display filter makes it easy to mess around with the image colors while getting a constant preview of the printed colors.
Giving an image might be misleading, as the image color would be additionally distorted by the scanning or photographing process.
My experience, though, is that printing tends to make things look somewhat darker and less saturated.