What is a website where you can make and edit a powerpoint with other people from your homes?

Microsoft Office Live.

Do you need the real Power Point program or are you just trying to make a power point?
If you want to make a power point collaboratively I highly suggest Google Docs. It’s not as robust as Power Point, but it gets the collaborative part done.

You might want to try out SlideRocket. Google Docs would also work, and I suspect eventually Google Wave will work too.

I second the Google Docs. Not as feature packed as MS or OO but it gets the job done well.

Otherwise I think Zoho has some collaboration support.

+1 for Google Docs and Zoho.