the opposite of IN is NOT IN
... WHERE id NOT IN (1,2,3)
this is documented here: http://dev.mysql.com/doc/refman/5.0/en/comparison-operators.html
an equivalent condition is --
... WHERE NOT ( id IN (1,2,3) )
however, do not make the mistake and omit those outer parentheses --
... WHERE NOT id IN (1,2,3)
this is not the same thing!!