To display karaoke style display (the words get highlighted as they are sung), use iAudio LDB manager which you can download for free. Once installed, add your MP3s and select them all...then "mark". You need to select S9 on the top left against lyric database. All lyrics found will attach themselves to the tracks. Don't forget to turn on display lyrics on the J3/X7.
A less satisfactory but still effective way is to copy and paste lyrics on the web into notepad and save them on the player. As the song is playing you could read the lyrics through documents.