This website calculates your commuting cost and compares it to other cars.
It's very useful and the numbers are close to what I have calculated. You input your home address and work address and it will automatically calculate the "fuel" cost for 4 different cars. The default cars are the Civic, Prius, Volt and Leaf, but you can change any/all of them. You can even change the price of gas and price of electricity to match where you live.
I played around with it for a while and decided to calculate my annual cost. I estimate that I drive 25 miles a day on my Miev, so I found two locations that are about 12.5 miles apart. Then I changed number of commute days from 5 to 7. It came up with an annual electricity cost of around $300, close to what I have estimated. And it calculated that I save over $1,000 a year compared to a car that gets 25 mpg - I used a 2008 Scion Tc which is my second car and which happens to get 25 mpg. My daily electricity cost for my Miev is less than $1.