Where to park depends on where you're going. Historically, Biketoberfest festivities are mostly associated with Main Street on the beachside in Daytona. For that, you can park in the Ocean Walk parking garage. It's two blocks from Main Street. You can find parking spots on the side of the Main Street.
Another center for Biketoberfest is Destination Daytona just North of Ormond Beach.This is a large motorcycle related retail and entertainment complex that was built by a Harley dealership in downtown Daytona.
And of course there's Daytona International Speedway, which is where all the actual racing takes place. There's plenty of parking there and signs to get you to it.