Do you have these songs on MP3 files or MIDI files??
--if so--
First you have to convert these songs into .wav.
You can get a converter in the DLDB (I think)
But sometimes the file gets big (like 30 megs) if you use the whole song so open up Sound Recorder and record you song through a microphone.
This will decrease the file size but will also decrease the quality.
You can also open up the file in the Sound Recorder and save it as a 8-bit.
That can also work but will decrease quality.
Good Luck