Google Presentation launched as part of Google Docs this evening. You can find it listed under the New menu list of the main Docs page. It can import Microsoft PowerPoint slidedecks (older PPT format, not the new PPTX 2007 format). However, it does not export to PowerPoint file format. It can, however, save a ZIP file to your local drive containing an HTML slideshow.

I created a test two slide deck without minimal effort. Google provides a handful of themes to choose from. I hope they open up the API to let user contributed themes to be used. This definitely does not compete with Microsoft PowerPoint. But, it might give OpenOffice.org Impress a run for the money. It looks like a useful tool that a lot of us will use to create quick simple presentations.