This article includes a Powerpoint presentation on Global Warming - the first such presentation published on theoservice.org, using technology by Scribd.  Scribd is an excellent way to bring presentations and a variety of other document types to the Web.  According to a Wikipedia article, Scribd supports the following document types:

• Microsoft Excel (.xls, .xlsx)
• Microsoft PowerPoint (.ppt, .pps, .pptx)
• Microsoft Word (.doc, .docx)
• OpenDocument (.odt, .odp, .ods)
• OpenOffice.org XML (.sxw, .sxi, .sxc)
• Plain text (.txt)
• Portable document format (.pdf)
• PostScript (.ps)
• Rich text format (.rtf)

This presentation on Global Warming is by "Andrew" (no last name).