大學教授與講師有何分別？

Except for teaching, they are totally different.

Lecturers, in a simple way to explain, are basically people hired by the institution for solely teaching without other responsibilities. Depending on the institutions, a Lecturer does not necessary possess advanced education qualification, and can be simply a professional in the field in order to become a lecturer (for example, a CPA for entry-level accounting course).

A lecturer can be a part-time or full-time position, but contracted. They are usually not an official portion of the institution, so they can't be promoted.

On the other hand, professors are academic staff of the university. In addition to teaching, professors may have additional responsibilities, such as management (like department chair, superior of the lecturers), student counseling, research, as well as money-making (seeking grants). As a result, professors are mostly full-time and can be promoted (tenure track). A professor must possess a related field research doctorate degree in order to be qualified.

2013-09-03 12:08:44 補充：
Professors also supervise student researches as well, but not lecturers.