PowerPoint is available to demo from the Microsoft website, if you just want
to use it for a brief period.

Interesting choice to ask on the Support Group for a product, what other
programs can be substituted.

Here are some ideas:

Easel, large paper,and markers.
MS Word and make a distribution handout
MS Publisher and make a handbook
Windows Movie Maker and make a movie

You may also check out some of the open office products, but support is
sketchy if you encounter any difficulties.
You can Google search for other softwares, they are out there.  I prefer
PowerPoint, but to each their own.

There's Open Office.  It has a PowerPoint-somewhat-like program.
I've tried it a time or two and found it a bit clumsy, but maybe that's just
because I know PowerPoint and Open Office is not PowerPoint.  To clone a phrase.

http://www.openoffice.org/

And if anybody asks, it wasn't me what told you.  
It was some other guy pretending to be me.
Yeah.
That's the ticket.

If you have MS Publisher, you can create a web design with menus and then the
file opens in IE.  You won't get any dynamic capabilities or animations
though.  PPT is a great tool though if you need to do presentations.  What
programs do you have currently? What is your budget fr purchasing a new
program?