For Mac users, you may have to convert the .aac songs to MP3 in order to get them to work. You can do this easily in iTunes. Here's how.

In your library, highlight the song or songs you want to convert. Go to iTunes preferences, advanced, importing. Make sure that the Import using pull down menu shows MP3 Encoder. Close preferences and in iTunes click on the Advanced pull down menu. With the song or songs you want to convert still highlighted, choose convert to mp3. After it's finished you will have two copies of each song you converted. The original aac and the new mp3. You can delete the aac or keep both. The mp3s can be moved into the MY OnlyMP3 Converter folder on your MiniSD (make sure you don't put them in the MY MP3 Playlist folder) card then the card can be put into your LG VX9800 cell phone.