this tune is usually played in the key of G on a C box but can be played in the key of C as well if you want to be different from everyone else. If you are playing it in the key of G then you can modulate to the key of F if you want to, your choice.
Thanks Aaron. I had been playing it in C because I had been playing everything in C. The bottom half of the keyboard intimidated me. Now that I have gotten somewhat comfortable (for me) with the G end, it has opened up a whole new world. Man this thing is cool.