Real America is a term used to describe the real spirit, ambitions, values, and attitude of the United States. "Real America" generally refers to the traditional values on which the United States was founded, such as gun ownership, faith in Jesus, and conservative ideology. John McCain used the term to describe citizens in central Pennsylvania, whereas Sarah Palin used the term in South Carolina (at least). Liberals do not believe in this term and do not acknowledge that small towns are the core of the country.
Sarah Palin popularized the term during the 2008 Presidential Election, but it predates her by several years; notably Glenn Beck wrote a book in 2003 entitled "The Real America: Messages From the Heart and Heartland."  The thesis of Beck's work was that liberal pundits have worked hard to undermine America's strength, greatness, and power, and that only Real Americans remain unaffected by this.
The term was also used in 2008 by Republican Rep. Robert Hayes, who observed in a speech in Concord, North Carolina that "liberals hate real Americans that work and accomplish and achieve." In making this observation, Hayes, like Beck, appeared to be indicating that being a real American was a matter of political orientation rather than simple geography.
If Real America is considered in a geographic rather than a political sense, then, primarily, red states can be considered Real America, but there are some towns in blue states (usually not close to cities) that can be described this way.
It is a short-lived political theme, very similar to the "silent majority" used in the political rhetoric of Richard Nixon.