Is there a way I can take the vocals of one song and transfer them to a different song using this program? I want to put someone's voice over someone else's song. Thanks in advance for any and all replies.
Regardless of the fact that you didn't specify what program you're using, it's generally not possible to isolate a single track in a musical piece that has already been mixed down. To perform this kind of operation, you would have to have access to the original arrangement, e.g. multi-track tape. This technical limitation is just based in the nature of a multi-track recording and mixing procedure.
Like ralftaro said, you're going to need a multi track program to be able to record vocals over a piece of music... As far as removing the vocals from a song already mixed down - he is also correct and you won't be able to remove them fully (you would need the original multi-track recording.)
You can however go and find Karaoke tracks which are in essence the complete arrangements of songs only the main vocals have been removed and then put your own vocals over them.
Great answers so far!
Let me add that you can, with Music Maker, make much of the vocals disappear either by copying the track and inverting the phase or with a vocal remover VST plug-in. Then you can re-record your new voice over. So there is hope at stripping the vocals from an existing song but it will leave some artifacts from the original recording. As long as you sing over it, it shouldn't be noticeable.