LAST EDITED ON Jul-14-10 AT 07:43 AM (EDT)
 
The proper time to begin salary negotiations is after you've put down whatever abomination SCIENCE! has just unleashed thus giving your new employer ample first-hand evidence of your abilities (and letting the abomination thin the herd of your prospective co-workers, making your own skills much more in demand and freeing up some of the department's budget).