I recommend going through a credit union. Check the yellow pages. Joining up usually costs $25 to put in your account. Once you get in, some offer interest rates lower than the banks...
I got 4.5% 2 years ago on my car. I think most around here are offering 5.1% now for newer cars. If it's older than 5 years, it will be a little higher, but that's still better than the 7-8% loans everyone else offers.