which board for USB communication with Novation Launchpad?

Unless that device emulates something standard such as a keyboard you won't be able to connect to it at all unless you find/write USB drivers for your platform.

It looks as if it is designed to interface directly to the 'Live' application (whatever that is) and not be used as a general purpose input device.

When you plug it in to a PC, does it appear as a standard keyboard?