Take note that you will need a cd writer and a blank cd-r/rw to burn your
presentation into a cd.

In PowerPoint 2003 and above, you can use package for CD (For 2003, File >
Package for CD. For 2007, click on the Office button > Publish > Package for
CD) and choose copy to CD. This will include a viewer which allows others
without PPT to view your presentation.

In PowerPoint 2000 and 2002, use Pack and Go feature:
http://support.microsoft.com/default.aspx?scid=kb;en-us;322107

You can also burn the presentation into CD, such as using third party
software such as Nero, or if you are using Windows XP, you can make use of
its feature: http://www.wellesley.edu/Computing/CDXP/cdxp.html

You might also want to check out how on how to make an autorun CD:
http://www.rdpslides.com/pptfaq/FAQ00037.htm

As a teacher I need to do this all the time. But because of computer
software compatibility problems, I find it more convenient to copy the
presentation to a memory stick/flash disk rather than writing it to a cd disk.