Open Office is open-source software. This means that it is open for people to improve and suggest improvements for.  It is free office suite that is fully-featured and has been developed over a period of twenty years. It’s pretty amazing and all yours to download!

Main features:

Comes with a word processor, spreadsheet, dynamic graphics, slideshow, database access
Reads the files from other office software
Has been used and tested by over 50 million people
Is constantly being updated– this is good!
Has an active community providing support
Comes with cool extensions – some free, some not
One install downloads & installs the whole package
Works on all major computing platforms– Microsoft Windows, GNU/Linux, Sun Solaris, Apple Mac

wikiHow has instructions on how to make an online presentation using Open Office.