There certainly are plenty of arbitrage opportunities all around. The definition of arbitrage is where you are buying and selling at the same time so aren't actually exposing yourself to exchange rate risk. But trying to do arbitrage manually I've gotten burned by not being able to do both trades quick enough and ended up losing a little on the trade. Other times, I've done arb trades only to regret having spent all of what little funds I allocate for arbitrage because shortly after an even greater arbitrage opportunity presents itself.
There still is a relatively fair amount of profit that can be found in doing arbitrage on a percentage basis, but without the ability to easily move funds to and from the exchanges, the profit barely makes up for the effort.
There are some tools that might be useful:
(USD, 6 hour delay without subscription)
(Useful for converting fiat from one currency to another,
e.g., Dwolla USDs -> USDs deposit -> USD/GBP trade -> GPBs withdrawal -> exchange
(EUR or GBP --> EUR, GBP, PLN or CHF )