In a statement on Friday, the FCC reiterated its commitment to extending rural broadband access by reminding everybody it is planning a reverse auction, the winner of which will receive a one-time payment of $300 million in order to fund the buildout of wireless data in rural areas. It's all a part of the FCC's revamped Universal Service Fund, which was originally designed to bring landlines to the far corners of the US but has been re-purposed for broadband access. Along with the reminder, the FCC took advantage of the MapBox online mapmaker and data from American Roamer to release a new interactive map showing the areas where it believes 3G coverage is lacking (which is to say, nonexistent). FCC Chair Julius Genachowski's statement pretty much sums it up:

As our new map demonstrates, millions of Americans still live, work, and travel in areas where advanced mobile networks have not been built out. Through the FCC’s Connect America Fund, we’re helping complete our nation’s wired and wireless infrastructure, which will lead to job creation, economic growth, and innovation in the 21st century.

You can zoom into areas of the map to find the gray zones where there is no 3G coverage as well as census data that should give you an idea of how many people are missing out. Unfortunately, the timeline for building out 3G and 4G in those areas is quite long, the FCC's reverse auction won't happen until September 27th, 2012.