Tony,

Visit this site:
http://www.users.globalnet.co.uk/~viper01/karaoke.htm

Click on the EXTRAS and MIDI links.
You can download 1440 free MIDI files and over 2000 KAR files.
The site owner has compiled them under one big zip file.

If you are looking for a specific MIDI do a search on

http://www.musicrobot.com/

Good luck,

Tapas