Great tips, Louann!
I started tracking mileage just over a year ago, Jan 2004, and I got a mileage booklet from the local newsagency/stationery store.
It sits on behind the steering wheel in a perfect location below my speedometer, so every time I get in the car I write date, speedo reading, and where I'm going - I also add "client" and name if I'm off to see a client.
In Australia [where I'm writing from] you have to do this for a specific period of time and then you can work out the percentage of biz + personal mileage, then use that as a guide for taxation purposes.
As long as we can provide the initial mileage booklet to justify, we can claim say 80% of all mileage, petrol/gas, car expenses etc.
But you know what?
I got so used to doing it, I have kept it up, even though I don't have to!
I also make an entry in the booklet when I buy petrol/gas, and what it cost.
It's such an easy thing to do and takes about 30 seconds ...
Cheers!
Teena