I was trying to find out if y USB ports were 2.0 or not the other day. The general rule of thumb, apparently, is to look in the device manager - if the USB controller menu has "fast USB", "Hyper USB", or similar names then it's 2.0. If it just says USB then it's older.
Also, most machines made before 2002 are USB 1.0.
I haven't found anything more specific than that.