All serial-USB converters are completely transparent in operation to your Windows apps, including whatever scanner software you have. That's because, once you plug-in the adapter to the USB port, Windows detects it, you install the drivers the first time, and then it just becomes a COM: port. like any other COM: port.
And all apps that require a COM (serial) port require is a working COM port present.. it doesn't matter if it's a motherboard-mounted type, or one from a Digiboard, or a COM port on a PCI card, or a plug-in USB-serial type. There's no "checking to see if it's compatible" with certain apps.
I use one from Trip-Lite, but they are a dime a dozen froma variety of manufacturers and pretty fool-proof. You can get them all day long on Ebay for maybe $10.
I'm mainly referring to Windows XP here, but should apply to Windows 2000 as well. I'd say most have drivers for Windows 95/98 too. Vista? no idea about that. I've heard all kinds of horror stories about Vista.
Good luck