I have had the times where I have used a usb networking card, or other device, and it didn't show up, although I was not sure if it was compatible with OSX. I just was not sure if OSX had a way to scan incase it did not recognize it, or if you needed to install a driver.
Is there a way to see what hardware is on the machine, like a device manager?

About This Mac, then clickMore Info.... System Profiler is the most Device Manager-like thing on the system. It doesn't have actions (update driver, roll back, uninstall, etc.), however. Oh, and if you're on Lion, you'll have to clickSystem Report...on theMore Info...window. – Jason Salaz♦ Jan 13 '12 at 20:49