Will songs from Napster work with my ipod?

I have the Napster program and I have it to when I download a song, it gets saved to my "my music" folder. I know napster isnt compatable for and ipod (by the way, I have napster to go) so what Im going to do is open the ipod files and then open my "my music" file and transfure all of the songs from my "my music" folder to the ipod music file. All I want to know is before I get the ipod is that will it work. Napster's file type I belive is WAV. or WMA. I cant remember, but please help me out, thanks!