Can a bank set interest rates below to prime rate or do they have to set them at Prime rate?

The Prime Rate on a mortgage loan at the banks in my area is about 6.1%. Can the banks set interest rates lower than the Prime Rate or do they have to go with the Prime Rate. If so, is there any other source that I can go too (e.g. credit union, mortgage company, etc.) [...] http://bit.ly/m7ppHk