edit: the new restrictions on sv usage (and cost) means that this extension no longer really works. Sorry!
chrome extension to list all (current and past) streetview panorama ids in an area drawn on the map, with metadata (plugin, instructions for loading plugin via developer mode).
you can download current or historical (usually more datapoints) panorama metadata. at the bottom of the page is a utility to download a single panorama in a variety of qualities.
another project has a java utility to download images from a list of panoramas ids (mosaic)