It just keeps getting easier:

http://onearth.jpl.nasa.gov/gis-wms....0.7053,51.8272

At this site the images are already in unprojected lat/long, are
automatically clipped to lat/long limits, and are already in
attractive pseudo-natural colors. There are a few clouds here and
there. The registration has been within 400 feet or so in the few
places I checked.

For more detail at extreme zoom substitute "pan" for "nopan". Details
emerge, but colors aren't as nice (details sharpened by 15m resolution
monochrome image - colors muddied).

I'm told up to 4096 by 4096 is downloadable. Make tiles to suit your
bandwidth and patience by adjusting width, height, and bbox (lower
left - upper right; West longitude negative)

Here's Fairfield, PA (.5 deg by .5 deg) with height and width adjusted
to match 6378.245km round earth at 15m resolution (WGS-84 scale
calculations are left as an exercise to the reader):

http://onearth.jpl.nasa.gov/gis-wms.....5,39.5,-77,40

Enjoy!

Jonathan Gere