The Federalist Papers are now on-line and searchable, thanks to Edward O'Connor who explains his reasons for providing this great service, and details about the site, here. It's a great site. The search function seems to work very well. A search takes you to google (see search results for "executive power" here), but when you click on the links, it takes you back into the Federalist Papers site. And individual papers are beautifully formatted. Nice touch.
Thanks to Cliopatria for the tip.