Uber.com offers the possibility of earning extra money by driving people around your city.
It appears to be crossover between a taxi service and ride share service. Although there is not much information on the website they do say that if you get if you get approved by them they send you a phone with the Uber app on it. The app looks like it will work by people registering they need a ride and drivers with the app can arrange to pick them up. (to be confirmed).
As an Uber driver you set your own schedule and use the app to get extra work when you want it or when you need it
It appears to be quite new so there are not many cities are available yet, but they do ask you to say which city you want Uber to come to next in their frequently asked questions.
If you are professional driver you can drive in almost any city where Uber is available. In other areas a sharing option is available where you can drive your personal car.
The requirements vary depending on the country and city you will be driving in, so you will need to check their website to see the requirements relevant to you.
While the options are currently limited this could be a company to watch out for in the future and is worth signing up for asking for it to come to your city, and you should also contact them about the option for ride-sharing if you want to use your personal car.