Hi Michael,
I'd offer several things to consider when adding currency pairs to your Dow trading. You'll see in many threads here on ET discussing that support and resistance seems to be well-behaved and respected by many of the currency pairs. (Trade up to resistance, bounce, repeat, fail or succeed, break through, trace back, bounce off of now support, etc.) You'll get the best feel for it just by watching it for a while. The best part is that nearly all feeds are free and in real time.
The EURUSD is most active during European market hours and US markets. It really quiets down after the 4pm ET close, but starts back up again around 10pm or 11pm (Eastern time, for reference). If you trade longer moves, this may not be an issue for you. If you trade shorter term, you might look at premarket trading, rather than aftermarket.
You'll see much heated debate about ECNs versus dealing desks. If you are used to trading the Dow in a centralized marketplace, you might find a dealing desk like OandA's to be preferable, more comfortable, and more like your daytime trades. ECNs have the potential to trade locally but will route into the interbank space if the quotes cross yours in the book. Both have advantages and would be worth demo'ing to get a feel for. My choices are OandA, IB, and MB Trading; however, that's a personal decision for each trader to make. Do be careful in choosing your dealing desk broker, as you can read many horror stories. I know that some use unfair tactics, but based on some of the rants and stories you'll read, it's apparent that it can come from trader inexperience as well.
Spreads will change based on time of day as well. That'll be true on the ECNs as well as the dealing desks. This will be no surprise to you, as it'll look just like what you see now in the futures.
