How can I get auto insurance for a car not in my name?

I have the opportunity to take over payments on a car. Since the title is not in my name, how can I get auto insurance for this car until the title is transferred into my name? I'd heard there is a form that the owner can sign that verifies that I will be the only one driving this vehicle. Any suggestions would be helpful.
Am, can you give me the website to your insurance company 21st?

Hey I just recently had this same issue the car not being in your name is not a problem!!! I have 21st century insurance!!! I love them!