Some of the advice in the following web pages is repeated, but I recommend reading all of them. I chose the most concise sites with the best tips, so it should not take you long to read all of them.

• An example PowerPoint presentation with source - courtesy of John Gennari
• How to give an academic talk
• Hints for good presentations (seems to be down for now)
• Guidelines for the preparation and presentation of technical seminars
• Presentation hints - focuses on presentation style, which is incredibly important!