where to find questionnaires for dissertation?

If you want only the MLQ (multifactor leadership questionnaire), you may refer to the following.

Bass, B. and Avolio, B. (2000). Multifactor Leadership Questionnaire: Sampler Set: Technical Report, Leader Form, Rater Form, and Scoring Key (2nd ed.). California: Mind Garden.

Since you mentioned the MLQ as an example, what other types of questionnaires are you looking for?

2007-04-11 17:29:54 補充：
For leadership effectiveness, I have a little suggestion but I do not know whether it is time-consuming and helps you or not. If you can read pages 352-358 ofCovey, S.R. (2004). The 8th Habit: From Effectiveness to Greatness. New York: Free Press.

2007-04-11 17:30:09 補充：
There is a summary over 20 leadership theories (of course including Kouzes and Posner, Yukl, and others) within those 7 pages. If you can trace back to the original work of these authors, you may see how a leader is effective and whether there are any useful questionnaires for your dissertation.

2007-04-11 17:43:12 補充：
I really cannot tell whether the MLQ is the most appropriate for you or not. However, I came across a small critic today.

2007-04-11 17:43:35 補充：
The only empirically derived measure, the MLQ, does not consistently allow for serparate identification of the various behaviours (Tepper and Percy, 1994), although new research indicates that the measure offers better validity and reliability than previously thought (Antonakis et al., 2003).

2007-04-11 17:44:02 補充：
Tepper, B.J. and Percy, P.M. (1994). Structural Validity of the MLQ. Educational and Pyschological Measurement 54: pp. 734-744.

2007-04-11 17:44:15 補充：
Antonakis, J., Avolio, B.J. and Sivasubramaniam, H. (2003). Context and Leadership: An Examination of the Nine-factor Full-range Leadership Theory Using the MLQ. The Leadership Quaterly 14: pp. 261-295.

2007-04-11 17:47:53 補充：
In view of the time constraint, I cannot read and summarise the above literature for you. I must add that I am NOT sure whether they are relevant or not.