There is a lengthy answer to the question "What is the current percentage of vegetarians and vegans in the us society as well as worldwide?" on Google Answers from March 2006. (This answer, I might add, was worth a total of $175 to the questioner, so check it out!) Among other things, the answerer acknowledges why this is probably an impossible question to answer for most parts of the world (though you may wish to see also polling results about the U.S. from Vegetarian Journal and statistics about Great Britain from the Vegetarian Society (UK)).

Going about your question from the opposite angle, then, I hope you will find it helpful to consider statistics on meat consumption by country. Online is the Food balance - meats indicator table from the Food and Agriculture Organization of the United Nation's FAOSTAT. This table, dated 2001-2003, includes figures on consumption, as well as production, export, import, for about 200 countries. If you calculate these figures with country populations (from a source such as the CIA World Factbook country profiles), you could get some per capita meat consumption figures that may be useful to you.

You can also search consumption by commodity by country or region in the core consumption data query area on the same FAOSTAT site.

I will send you the following tables from LexisNexis directly:

• Projected Changes (Percent) In Total Meat Consumption In The Developing And
  Developed Countries, 1990-2020 , Issued By: Forest Service , Publication Date:
  December, 2000
• Meat Consumption By Type And Country: 2003 To 2004 [Beef And Veal, Pork, And
  Poultry] , Issued By: Bureau of Census , Publication Date: December, 2005
• Meat Per Capita Consumption Projections [By Country And Region, 1999-2014]
  [Part 01: Australia-New Zealand] , Issued By: Organization for Economic
  Cooperation and Development , Publication Date: 2005
• Meat Per Capita Consumption Projections [By Country And Region, 1999-2014]
  [Part 02: Norway-South Africa] , Issued By: Organization for Economic
  Cooperation and Development , Publication Date: 2005
• Meat Per Capita Consumption Projections [By Country And Region, 1999-2014]
  [Part 03: Other Africa-Other Latin America] , Issued By: Organization for
  Economic Cooperation and Development , Publication Date: 2005

In terms of books and articles, there is a vast bibliography on "Meat-eating and Vegetarianism" (last updated 6/06) from an anthropology professor at Illinois State University.