how do you change the odomoter from kilometers to miles

Should be as simple as pressing a button on the dash cluster or information panel.

You use the same button as you use when you change the time. If you press the button you can change the hours, press it once more and you can change the minutes and finally if you press it once more you can change between miles and kilometer....I think. Some time since I did it so I'm not sure.

Not sure about 986's, but on my 987 it is done either from the computer stick on the left side of the steering wheel, as follows: Push, Scroll down to set, Choose units, set them! The other way is via PCM settings!!