The best way would probably be to create html-files, and get tham opened in Powerpoint by setting the mime-type.
I use this to create "excel"-files:
header("Content-Type: application/vnd.ms-excel");
header("Content-Disposition: filename=\"filename.xls\");
The document is plain html-tables. The results are really great, and most users wont notice that this isnt "real" excel-files. You can even use css in the html to change colors, fonts etc. And you can use images. Another positive side-effect is that the created files are readable for people not having excel.
The code above opens Excel as an embedded object on my computer. Different windows/excel versions varies. It might open Excel... it might give you a save/open dialog. You could also try adding "attachment" (in "...Content-Disposition: attachment; filename=...")..
As to PowerPoint my results havent been that successful. But I havent really tried it much. It does read html-files, but I dont know how to fool it into making extra slides. By changing the mime type to "application/mspowerpoint" it opens everything on one slide. (and in most ceses this is not really what you need)
You might be successful if you try to set page-brake in css, or using iframes, frames... I havent time right now to try this. If anybody knows how to do this, please tell me. I have some future projects that might need this...:-)
