Gas Price Tracking Websites, et al

There are a number of different websites, which all take a number of different approaches, that track gas prices and can tell you where the cheapest gas is in your area. The two that stand out to me are (in no particular order):

MSN Autos - Local Gas Prices, the upside of this site is that their pricing data is provided by OPIS (Oil Price Information Service) - which makes it accurate. The downside is that OPIS data, even though it is updated nightly, might not be truly up to date. It may be up to 7 days due to the electronic processes by which they collect their data (e.g., through credit card transaction records). As well, the mapping element is provided by MSN MapPoint - which means that you can't scroll a map the way you can with a GoogleMaps mashup (in fact, you can't scroll this map at all). You can zoom, though, within the specified zip code without requiring an annoying page refresh.

Map Gas Prices, the upside of this site is that their mapping element is provided by GoogleMaps, so you can scroll without requiring a page refresh. Also, users can enter pricing data directly - which means that this site may be more up to date, but it also may be inaccurate due to the possibility of human error. It is unclear whether all of the pricing data on this site is obtained merely through user input (which I doubt, since 110,000 price points is an awful lot of user input), or if user input simply supplements data acquired through other means, e.g., OPIS. Another nice feature of this site is that you can sign up for automatic alerts via email for the lowest price point near you.

Map Gas Prices is produced by a company called Orbizon, Inc., which also produces a site called Map Sex Offenders, which (yes, you guessed it) displays the registered street addresses of registered sex offenders on a GoogleMaps map - this data is compiled from the web-based databases of various states.