I did a quick search in LW for S.P. & came up with these formats: mp3 (lol), avi, rm, mpg, mpeg. The most common one's listed in order from 1st.

rm format is real player.

http://www.rmconverter.com/ if you wished to convert them.

BH also came up with some odd one's in wav, bin & m4a (mp4)
B came up with a couple in wmv format. But again the most common are in the initial list above. So whatever player you're going to use I presume wmp should be ok.