The Unashamed Workman blog has a list of arguments for and against the use of visual aids like PowerPoint in sermons. It is a compilation of the comments that the blog received on a previous post. Some of the interesting ones are:

FOR

1. Visual images were frequently used by Jesus to illustrate the word he preached.

AGAINST

1. It shows a lack of confidence in the word preached.
3. It can produce a ‘lecture feel.’