You can purchase powerpoint on it's one (standalone)
Or it comes with microsoft office (even the small business edition of office 2003 includes powerpoint)
The current version is powerpoint 2003
previously it was 2002/XP
before that was 2000
and before that was 97
before that was not worth bothering with
Cheers
TAJ Simmons
microsoft powerpoint mvp
awesome - powerpoint backgrounds,
free powerpoint templates, tutorials, hints and tips etc
http://www.powerpointbackgrounds.com