grasshopper31,
Well, without knowing what plane you are trying to fly and your experience level it's a little hard to give concrete advice, but let me venture a couple of educated guesses. As an instructor I can tell you that there is one universal fact when it comes to beginners, they over control the plane. Meaning they move the stick more than is needed. Every new student does it, so it's not something to be embarrassed about. I'd be willing to guess that is what is happening here, you are simply putting too much control in and causing the plane to act this way. When I am teaching a new student to fly I usually won't let them take off until I see that they have started to overcome the over control issues.

Also, as Chuck mentioned, if you are using the Cub you mentioned earlier then I'd say it's partly the plane. Cub are notorious for acting just as you described on the ground. That combined with the over control I mentioned above results in a situation that drives a new pilot crazy.

I have to ask if you have an instructor helping you on your flying?? If not the ground loop you are experiencing may be a minor problem compared with what you will face as soon as the plane is in the air. The instructor should be taking the plane of until you've overcome the over control issues.

Hope this helps

Ken