During my adventures trying to understand foreign exchange, I found out eoddata.com only stores 9AM-5PM forex tick data. I was curious if there was a good historical provider that has historical forex data. I was thinking maybe of a way to get them at least in month-long blocks--at least a few days at a time.
Dukascopy has free data for a number of time frames. It should be right on the homepage of dukascopy.com
Integral has a retail facing site that offers tick data for their liquidity feed: truefx.com Someone already mentioned Dukas as well. . .
Olsen (Oanda co.) has tick data: http://www.olsendata.com/data_products/welcome/ Edit: Disregard, it's 45k Euros/year.
I keep finding proof the Swiss are cool people. I managed to get their EUR/USD data for a week, which should be plenty to understand superficially how stuff moves. I'll check the other suggestions here too though, one at a time.