Given the iPhone's ability to locate itself (precisely, for an iPhone 3G, and roughly, for a first-generation iPhone or iPod touch), it's not surprising that a number of location-aware programs have sprung up in the App Store--you can find programs that will track your iPhone via its GPS chip, show you where your friends are, and tell you which businesses and places of interest are in your immediate neighborhood, such as Yelp.

Another task that seems to fit well with a location-aware iPhone is finding the nearest--and least-expensive--fuel for your vehicle. In this era of US$4.00-per-gallon gas--yes, non-U.S. readers, we know we have it comparatively easy--saving as much money as possible on a fill-up is a good thing. But can the iPhone really help you save both time and money by finding the least-costly nearby gas station?

To answer this question, I installed three gas-station-locating applications on my iPhone 3G--the free GasBag, the $3 iGas, and the free MyGasWars--and put them to the test. (Note that some of the multi-service location-aware applications also include gas finders; I'll cover them briefly in the Other Options section.

In evaluating these programs, I tested them from my home (wireless network), from a location in the downtown area of our mid-size suburb (3G network), and out in the country (EDGE network). I was curious as to how many stations would be found in each location, how accurate the provided pricing info would be, and how easy it was to get driving directions from your current location to a chosen gas station.

The country location in particular was chosen to see how well the programs worked away from a population center--it's usually pretty easy to find a gas station in the city. The spot I picked was actually in the parking lot of the only gas station within about a five-mile radius of that spot, and it's not a chain gas station, making it less likely that it might reside in a database somewhere. I was curious to see which of the programs would know about this out-of-the-way station.

All of these programs will be most accurate with an iPhone 3G, as it provides your specific location to the program (assuming you have Location Services enabled in Settings). If you've got a first generation iPhone or iPod touch, you're not out of luck, however--you can input a zip code or city to help pinpoint your location. (Because I only have an iPhone 3G available for testing, I was unable to confirm how well this feature works on other devices.)

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