Perhaps the best use for the MBTI is for self-reflection. If used as a starting point for discussing how people vary in their personalities, and emphasizing tolerance for individual differences and taking others’ perspectives, then it can be a useful tool. However, it is important that the test administrator caution against over-interpretation of the results, and discuss the limitations of the instrument.
For good, detailed criticisms of the MBTI, here are some references:
Pittenger, David J. (1993). The utility of the Myers-Briggs Type Indicator. Review of Educational Research, Vo.. 63, #4, 467-488.
Pittenger, David J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, Vol 57 #3, 210-221.