A Technical Question

I'm working on my SCBWI talk for next month, and I don't have PowerPoint on my laptop here at home. Is there any free Web-based presentation software out there you'd recommend? What I want is something pretty much equivalent to PowerPoint -- e.g., I can make slides and, using a projector, show them on a screen. I just need the program that would let me make the slides, with bonus points if I can save my slides to an account on the Web within the program. (I was hoping Google would have something like this, the same way they have Google Documents as an equivalent to Microsoft Word, but I wasn't seeing it.)

Thanks for any and all recommendations!