TIP 1: I use kareoke CD's as the originally sung lyrics of a song would interfere with what you are trying to sing in the target language in the classroom. Ones that I have used in the past come from the Avid label from which I have used the Kylie Locomotion successfully with Spanish Classroom language (cheesy kareoke beats but it does the job - I'll add the PowerPoint with lyrics...). However, this time I used an Abbamania CD which is less cheesy but does have light singing of the chorus in the background (no bad thing if the song flops in class eh?).
TIP 2: If you need access to the original lyrics of a song to work out the rhythm of the words without incessantly rewinding (gosh that just made me feel old!)/ replaying your music source, try a lyrics website such as Lyrics Freak
It can take some time getting words to fit the tune of song, which is why I only tend to do it when inspiration hits rather than seeking to do a song for the sake of it. However, the results are worth it. One of my year 7 classes, to whom I taught Spanish classroom language using the Kylie locomotion tune, used to sing it, without prompting, whilst running around the track during their PE lessons (so I'm told!), and they could still sing it word for word when they reached year 10. On one occasion they burst into a rendition of it as I entered the classroom for a cover lesson those 3 years later. That was one of the best moments of my teaching career so far. Enjoy!