A recent posting in the discussion area of the LSIS eCPD programme gives a a very easy and useful way of integrating drag and drop into a live PowerPoint presentation. Nigel Davies's Powerpoint file includes the example, as well as instructions on how to achieve it.
Also don't forget Ron Mitchell's Picture Grid Editor, which you can download and then use to creat a drag and drop picture/word match. This outputs not just to PowerPoint, but to Word and web page format too. Best to look at the example here first, then download the software that allows you to create them yourself. (No install needed)