I would start by doing some research on SBA loans. Your local bank can help you with that as well.
How much of a loan are you looking at? Do you need to purchase equipment, pay employees, carry inventory, supplies, lease/rent office space etc. Do you have cash/assets on hand now? Keep in mind a marketing budget and how much cash flow you require to make monthly payments.
Do you have experience in this business? Do you know the current owner of this business?
I would start with a small local bank. Go to several if needed.