I’ve installed a new WordPress plug-in to display Facebook, Twitter, and Google+ buttons at the bottom of individual posts (not on the main page). If you have any problems using them, please let me know.
Update, 8 August: I had to turn it off, as it was interfering with the stylesheet for both comments and extended entries. In both cases, whatever it was doing was reducing the space between paragraphs to the same as the ordinary inter-line spacing, and treating bulleted lists as if they were just ordinary paragraphs.
Nice idea, needs either a better (less intrusive) implementation, or should only be used by bloggers who know much more about the innards of stylesheets than I do.