Smashing Magazine has written what must be one of the definitive articles on linkbaiting.
With headings like:-
What is Linkbaiting?
Profound Rules of Linkbaiting
Writing-related Principles of Successful Linkbaiting
Tactics and Strategies of Linkbaiting
Linkbaiting Hooks
Copywriting: Improve Your Writing Skills
Copywriting Books
And an incredibly comprehensive list of relevant links and resources this is definitely worth bookmarking.