Hi there LGF,
You can fish with clams bellies on a number of different bottom rigs really. Many people will use the standard fishfinder rig, while others prefer a single or double hook dropper loop rig. Either way, a 6/0 circle hook should work well. You want to make sure that you hook through the tougher meat to keep it on your hook. Some people prefer to cut the clam in half or in thirds, others (including myself) who hold to the "big bait=big fish" theory will leave the clam whole.
Don't be afraid to try out different methods where you fish. In some places you can KILL em on clam bellies and in other spots (like where I've been fishing) they're looking for different table fare, so experiment and see what works for you.
That's just my :twocents: Hope it helps!