If you really need to have it snappy, there are third-party programs that
can take your powerpoint presentation and convert it into Flash, which is
very easy to add to a web page. Tools such as Camtasia Studio
(http://www.techsmith.com/camtasia.asp) and PowerConverter
(http://www.presentationpro.com/products/PowerCONVERTER.asp) work very well
for this. The HTML version of the presentation will often work well, but
sometimes due to the effects/transitions/narratives in a presentation it
looses a lot or doesn't work for some people.
If you want visitors to you site to view the powerpoint, you can either
put a link to the powerpoint on a webpage or insert the powerpoint as a
flash slideshow on a webpage.
There is an article abouting taking a powerpoint to a blog and a blog
is something like a webpage. You can get some tips from it.