Here are some tips, tricks and resources for PowerPoint:
Office Online’s PowerPoint Page (2003, 2007, 2010)
Brainy Betty PowerPoint Tips and Tricks
Check out this great Mashable blog post if you are looking for presentation options beyond PowerPoint. Thinkfree Online is great.
Don’t forget the old tried and true OpenOffice Impress – here is a wonderful tutorial for it. Download OpenOffice here.