If you save an item from your web browser, Finder’s Get Info will show you its original URL. But there’s no way to get that information as selectable text later, unless you want to do it in Terminal and know the vagaries of the mdls command. Waaaaay too complicated.
So here’s a quick script that solves that problem. Highlight any .webarchive file (or other files which have Where From information), and up pops a dialog box with that information in all its selected text goodness. (Technical details: the script gets it from mdls with flags -raw, and -name kMDItemWhereFroms. Heck, I know how to use mdls, and I think that’s too much typing.)
Download wherefrom-10.scpt.zip.

WhereFrom 1.0 by Jeff Porten is licensed under a Creative Commons Attribution 3.0 United States License.