Would guess that it's 1.1, but USB is backwards compatible, and you can always buy a USB 2.0 PCI card for little bucks to get the extra speed if really needed.
I have an IBM, with windows ME. I think it is about 3 years old. I need to know where to go to find out if my USB port is a version 1.0 or 2.0. I want to buy a USB Flash disk and someone told me I needed to know the version of my USB port.