American superheroes are packing their bags for what they hope will be a profitable trip to India and China.

Marvel Entertainment (MVL) says it has created an international advisory board in an effort to cash in on the success of its recent films, as the huge and growing populations of India and China offer solid prospects for future growth. Marvel says international sales could generate about 50% of its revenue in 3 or 4 years.

Marvel’s first self-produced movie, Iron Man, generated more than half its revenue in international markets. The movie was distributed by Viacom’s (VIA) Paramount Pictures.

Marvel’s decision to expand into India and China underscores the emergence of a worldwide market for popular culture. Hollywood movies have long been profitable overseas, often outselling domestically produced films in some countries. The recent success of Slumdog Millionaire -- a movie set in Mumbai and produced in India -- shows the international market now moves both ways.

British pop stars repackaged American blues for US audiences in the 1960s, but entertainment now seeks to extend beyond the Anglosphere - or English-speaking nations that share a common cultural heritage. The move is almost certain to spark cries of “cultural imperialism” along the way, resulting in regional efforts to remain culturally distinct.

There have been variations on this theme in the past -  Edvard Grieg’s efforts to define Norwegian music come to mind. He did it by way of the Leipzig Conservatory, and is perhaps best remembered for Peer Gynt. But who thinks of Grieg as just a local boy now?

The universal language of the late twentieth century was distinctly American - international travelers could routinely find McDonald’s, Coca-Cola or familiar sitcoms on TV.

But American superheroes may have to be tailored to meet international tastes.

Marvel has partnered with Madhouse -- a Japanese animation studio -- to recast its superheroes for the Japanese market, including new names, new looks and new storylines.

Movies appear the fastest and most effective way to introduce Marvel’s characters to international audiences; it plans to release self-made movies in 2010 and 2011. Diversifying the audience could be very profitable, especially if fixed costs remain about the same.

Marvel plans to decentralize its overseas expansion and tap local leaders as it sets up international operations. Clearly, Marvel understands that one size doesn’t fit all when marketing to an international audience.

It may come down to this: Godzilla offering Spiderman a Pepsi, a bag of Doritos, and an iPod.