Incredible Charts — A very good resource to learn everything about charts.
John Bollinger's Official Bollinger Band Website — Forex screening, analytics and signals based on Bollinger Bands. Interactive charts with a wide array of technical indicators and streaming Forex news. And totally unique on BB4X.com are patent-pending 2-D and 3-D charts.
FXstreet — Many useful articles, constantly added expert commentaries and forecasts.
LiteForex Blog — Forex articles, news and analytics.
Foreign Exchange Market — a Wikipedia article about foreign exchange market offers a detailed view and the history of Forex..
ForexFactory — a popular Forex discussion forum..
/r/Forex/ — Reddit community about Forex trading.
TradingView — create feature-rich Forex charts and share them with other traders.
FXSTAT — a network for currency traders to share their trading account activity and for other traders to follow that activity.
MyFxBook — analyze your trading account activity and share it with fellow traders. Watch detailed stats of other traders.
StockTwits — like Twitter but for financial trading posts. There are many good analysts to follow, but everything is too focused on stocks rather than currencies.