Joe Konrath remains both an author and an author's friend. I've learned a lot about publishing and about self-promotion from him in the last year. His blog is earmarked over to the right of this column if you want to sample him.
Today, he has an article on Backspace that should be a must-read for all writers. He talks about how to "do" an author signing.
This is one of those things that no one tells you about--probably because most writers do it "catch as catch can."
Joe offers some solid advice on things to do (bring donuts for the bookstore staff) and things not to do (don't sit behind your table). He provides a list of things to bring and a timetable of when to make calls.
Check it out at: http://bksp.org/secondarypages/articles/authors/JAKonrath3.htm.