How do I tell if my USB is 1.1 or 2.0?

Easy.

Applications->Utilities->System Information (might be called System Profiler if on an older OS)

On the left, find USB and click on it. It should tell you the USB version on the right (For example, mine says USB 3.0 High-Speed Bus)

FYI, System Information/System Profiler likely won't say USB 1.1 or USB 2.0

Look for the keywords "USB High Speed" and in the properties for it you should see speed listed as "Up to 480 Mb/sec"