FHA loans are government insured loans that pay the balance of the mortgage if the loan goes into default. This is used typically by first time home buyers due to it's ease of process and better interest rates, however, the mortgage insurance is higher than on conventional loans.
USDA loans are back by government funding and are used for rural areas, however, you'd be surprised what is considered rural. It's a good idea to check the USDA map when searching for a home. If you meet the income requirements, you just might be eligible for a USDA loan.
VA loans are for service members from both regular armed services and national guard. See if you qualify!!