The Logitech Pure-fi can work with non-iPods if you use the 3.5mm aux input. You'll have to supply the cable, which you can get at Best Buy, Radio Shack, and similar stores. The docking area will be sort of useless, but you can probably use the area to set the Sansa Clip on.
As far as the S100, you should be able to use them with any mp3 player. Instead of connecting the speakers to the computer, you connect them to the player via the 3.5mm line in (not the headphone input).
Are speakers like this: http://www.bestbuy.com/site/olspage.jsp?skuId=8439905&st=logitech+s100&lp=4&type=product&cp=1&id=1183160884884
only compatible with iPods?
Is the Logitech S100 compatible with all MP3 players?