Moisturizing creams may help soften the skin and remove cracked calluses. Put the cream on the callus and cover the area overnight with a plastic bag or a sock -- but only if your doctor tells you to. In the morning, gently rub off as much of the callus as you can with a rough towel or soft brush. Or you can use a pumice stone to rub off the dead skin from a callus after a bath or shower, then put a moisturizing cream on it.
There are stronger creams with urea that might be more effective, but don't use these unless your doctor tells you to. Don't bother with hydrocortisone creams -- they only help with itching and rashes, and may not be needed for calluses.