First, remember if you market is not covered by one of the internet provider, you have the ability to import data from a file.

Also, let’s agree on what “coverage” means. First, to do any technical analysis, you need historical data. Secondly, data are owned by the stock exchange companies, they are the ones selling licenses and there are several level of licensing, showing short term, showing historical data, enabling viewers to download history. What we need is the ability to download history. If you cannot manually download historical prices, chances are Mastock won’t be able to it as well.

Nevertheless, here are the links for the internet providers:

Yahoo:
http://finance.yahoo.com/exchanges

Google
http://www.google.com/intl/en/googlefinance/disclaimer/?ei=5W3cVvihO4e32AaGu7uoAg

Trading_ASX covers only Australia

kbd_Japan covers several Japanese exchanges

India_NSE covers the Mumbai Indian exchange

EODData:
http://www.eoddata.com/default.aspx

Quandl: covers many many exchanges, including currencies, futures and commodities.
http://www.quandl.com