I teach guitar, not just songs. Yes, songs are the finished product, but there is a difference between knowing how to play a few songs, and knowing how to play guitar. The difference is in not only knowing what you are playing, but why.
No, you're audience probably won't care if you know the names of the notes and chords you play, or even what key you're playing in. You play the songs for them, but knowing music and music theory is for yourself.
So, if you just want to learn how to play some songs, there are some great websites that can give you all you need to know. Save your money and use them. However, give me a call because you're ready to learn guitar, not just songs.