Many of my clients get confused between the Medicare and Medicaid programs, partially because the names of the programs are so similar. Another source of confusion is the fact that nursing home care is mostly covered by Medicaid (if you qualify), but Medicare also covers the first few months of nursing home care (under certain conditions). But I suppose confusion with government benefit programs is not unprecedented.
Please note that you don't need to worry about Medicare yet unless you're (a) age 65 or older, (b) under 65 with certain disabilities, or (c) any age with end-stage renal disease.
Anyways, here's a little primer on the Medicare alphabet. Please remember that the extent and length of coverage varies greatly depending on the circumstances.
Medicare Part A ("hospital insurance"): Covers inpatient care in hospitals. Also covers some skilled nursing care, hospice and home health care.
Medicare Part B ("medical insurance"): Covers doctors' care, outpatient care as well as some preventative care.
Medicare Part C ("Medicare Advantage Plans"): A health coverage option run by private insurance companies (like HMO's and PPO's). These companies have been approved by and under contract with Medicare.
Medicare Part D ("prescription drug coverage"): Prescription drug coverage run by private companies, approved by and under contract with Medicare.
That's as simple an explanation of the Medicare parts that you're going to find. But of course, there are lots of details. Please click here for the Medicare website, which is very comprehensive.