Let me qualify by saying that picking the currency markets is very difficult and if I could do it accurately, I'd be rich beyond imagination (which I'm not).
A useful indicator to what currencies are doing in the future (probably the most important indicator) is the relative interest rates between the reserve banks of different countries.
There is an interest rate table on the major curriencies:
http://www.fxstreet.com/fundamental/int ... tes-table/As you can see from the table, the US Fed is practically giving credit away at 0.25% interest which is really low especially considering back in 2007 they were lending at 4.75%. This says two things - one, the US economy is slow enough that the Fed is trying to stimulate it with cheap credit. The Fed is likely to be releasing a lot more greenbacks into circulation which is bad for inflation and bad for the relative value of the greenback.
The Bank of England is not doing much better, as they are lending at a very low 0.5% suggesting that the pound is likely to follow the greenback down in relative value.
The Euro is looking a little stronger with the European Central Bank lending at 1.5.%
Highest reserve bank rates (for a developed country) are in Australia at 4.75%.
Exports from Australia (mainly from mining) are doing so well that the Aussie reserve bank is putting the brakes on the economy and raising interest rates to restrict credit supply. This means not only are exports doing well, but the Aussie Reserve is printing less Aussie dollars keeping inflation down and pushing up the value of the Aussie. The only problem with the Aussie is it tends to be a bit unstable because of the small size of the economy compared to other countries. The Aussie has had a bit of a roller coaster ride over the last few months and took a 10% fall recently, but I think it's looking good at it's current price as the economic fundamentals are still sound.
I haven't researched this thoroughly myself yet, but New Zealand seems to be a very attractive country to invest in because they are a tax haven. There is usually no capital gains tax on investments such as shares. The relative value of the New Zealand currency tends to follow the Australian currency because so much of their trade is with Australia.