Does anyone know of a plug-in for managing data through a USB port?

It's not the USB port itself, it's what is plugged into the USB port.

What are yuou planning to plug into the port? For the most part the OS manages all that stuff, whether it be a barcode scanner or an external hard disk.

Interesting point. I was thinking it would work like a serial port that would need to be opened and closed.

Thanks much.

Jeff:

As Vaughan said, all the major operating systems handle the USB port pretty well. For example, with a USB barcode scanner in FileMaker, if the cursor is in a field and you pull the trigger on the scanner, it works as though someone had typed the data into the field...

-Stanley