Anyone can learn Forex currency trading online as there are plenty of online resources (an example is: www.OnlineForex.net) as well as trading platforms that will provide you with plenty of information. Forex stands for foreign exchange market and is one of the largest markets in the world. Today anyone can trade on the Forex market though for many years only large financial institutions where involved in Forex trading.
Trading on the Forex market is much different trading on the stock market. The Forex market deals specifically with different foreign currencies and unlike the stock market there is no regulation or governing bodies. If you are looking for easy transactions than this is the best liquid market in the world. All trades tend to occur based on credit agreements.
When the different values of the pairs change you can make money based off of your investment. This market is always open as the currency markets are always changing. So if you are looking at the US dollar and Euros you will buy Euros with US money, these money goes into the US money reserve, and if the exchange rate increases you sell the Euros and make a profit.