Statistics on the cost of living in various U.S. cities are compiled and published by the DOL's Bureau of Labor Statistics as the Consumer Price Index (CPI) and by the Commerce Department's Bureau of Economic Analysis as the Personal Consumption Expenditures (PCE) Price Index. To get CPI data, see the separate entry for the "Consumer Price Index." PCE data and a comparison of the PCE and CPI is available through the BEA's Consumer Spending page.
Calculations: You can get calculations of equivalent salaries from one city to another from The Salary Calculator and Datamasters' U.S. Cost of Living Comparisons. You can figure the comparative buying power of the U.S. dollar from one year to the next (back to 1913), using the U.S. Inflation Calculator.
Inflation: Inflation is the increase in the amount of money required to purchase goods and services. The term is often used synonymously. In the U.S., inflation is generally measured by the Consumer Price Index (see "Consumer Price Index"). An alternative measure is the Personal Consumption Expenditure Price Index published by the Commerce Department. Current and historical Personal Consumption Expenditure Price Index data is available through the Price Index and Deflators page posted by the St. Louis branch of the Federal Reserve.
Foreign: Statistics on the cost of living in various countries is published in the International Monetary Fund's International Financial Statistics. See the OECD's Prices and Purchasing Power Parities page for foreign inflation data, purchasing power parities and comparative price levels.