Pat,
I have found if one loves to sing, they should try a karaoke type of site that allows feedback. Singing on a semi-daily basis and being critiqued DOES help us to understand what other people are hearing in our voices.
I have used Singsnap for a few years now and it has helped my tone and pitch immensely. I have also listened to people who appeared to be tone deaf actually sing on key and in pitch after a few months of singing there. It does work for most people, singer or not. I have witnessed it myself with a few close friends there.
Pitch correction should only be used as a last resort, IMO. Practice, practice, practice is GREAT advice for us wannabe singers.
Trax