Here are some web pages that may be useful for finding further information on the topic of representation of minorities in media.

Very interesting web page is Media Awareness Network covering issues such as Stereotyping of minorities, ethnic minorities in the news, as well as disabled people, gays and lesbians and many others. Much useful information can be found on this site including statistics and findings of studies.
Link:http://www.media-awareness.ca/english/issues/stereotyping/ethnics_and_minorities/index.cfm

Another good page to visit for more information about demographical structure of the United States of America is America.gov. This page contains statistical information from 2007 Census. The article shows the development of American population since 19th century with the data being represented very clearly.
Link:http://www.america.gov/st/diversity-english/2008/May/20080513175840zjsredna0.1815607.html

For further information on the two current cases presented on this blog regarding representation of minorities in Czech media and political incorrectness Prague Monitor can be visited. Prague Monitor is an English-language electronic daily about the Czech Republic where you can follow both cases.
Link:http://praguemonitor.com/2010/04/16/romani-activist-criticises-childrens-book-racist