Ask YC: online presentation (shareable) software in place of Zenter?

Since Zenter was acquired, and Google hasn't yet moved the product into their lineup, what alternatives are there for online slide presentation?

http://mashable.com/2007/08/12/online-presentations/

Which of these would you recommend to use in its place in the meantime? I just basically need to throw together a slide presentation and then have it shareable by people going to a URL.