Download and install Audacity for free. Audacity is compatible with Windows, Linux and Mac Operating Systems.
Open the song you want to convert in Audacity by clicking on "File," "Open," then select the file. It may take a moment for the file to load.
Highlight the entire track by clicking and holding the mouse and dragging the cursor over the Audacity display.
Click on the "Effect" menu and select either "High Pass Filter" or "Low Pass Filter." These filters allow only high or low tones to pass through---in the case of high pass filters, higher tones are played; with low pass filtering, the lower tones are played. This is useful for removing the lyrics from songs that feature primarily high or low-toned singing. For example, the popular 1980s band "Rush" has many songs with deep bass music and higher pitched lyrics; in this case, a low pass filter would remove the high lyrics and let the lower-toned music play through. Of course, this does not work for all songs; if your initial filtering does not create the desired effect, press "Ctrl" and "Z" to undo the action. Then click on the filter again, but this time adjust the slider by clicking and holding, then dragging it back or forth to allow more or less sound to come through.
Download and install Video Karaoke to create a video of scrolling text to accompany your karaoke music. This is useful for singing along to the lyric-free music, as well as singing along to songs with lyrics present. You can also use related programs like Windows Movie Maker to create a scrolling text video.
Add the lyrics to your video and set the scroll speed using the program's interface. For help using more advanced features, press "F1" for the program's help library.