No. Again, though, a business license is a permit, issued by a local government, to operate a particular type of business, or to operate a business in a particular location. The thread title notwithstanding, it's not what's being discussed here.
Depending on your location and your bank, you may need some documentation of your business name in order to open a business bank account. That is, if you're not operating under your own name you should have a registered assumed name or dba and might be asked to document that.
But there's never a requirement that you incorporate in order to operate a business. The "sole proprietorship" is completely legitimate and recognized by everyone, including banks and the IRS.
[edited by: JayC at 9:57 pm (utc) on Dec. 17, 2002]