Best-selling SF author John Scalzi has this advice for people thinking about falsely using his name to promote their wannabe writing careers: "Certainly if I found out someone was lying about my association with them, I would go out of my way to make sure everyone knew what a lying sack of crap they were. And at this point I have a fairly loud megaphone."
Scalzi's advice comes in response to Justine Larbalestier's wonderful post on asking people for blurbs for a new book. Tobias Buckell also weighs in on the subject of blurbing. The long and short of what these three top-notch writers say: Ask nicely, don't bother the author if they don't respond, and don't be a lying sack of crap.
UPDATE: John Scalzi also gives some excellent monetary advice to wannabe writers. His best financial suggestion: "get the hell out of New York/LA/San Francisco."