i'm using this http://www.geovid.com/Presentation_to_Video_Converter
easy to use and intuitive interface, ppt/pps 2 avi/asf/wmv/mpeg conversion, option "burn cd/dvd" (it's also a cd-dvd-burner, wow!), no audio and video quality loss (many similar programs have problems with audio), options "auto click" (very useful!!!) and width-height changing.