Hello from freezing Sweden! That polar bear pretty accurately describes how I feel here -- really damn cold. I don't know how we traveled without the internet at our fingertips so here are five apps I've been using pretty obsessively this trip (excluding CityMapper, this issue.)
Since google bought and absorbed Word Lens, this has become invaluable. The app uses your camera and the internet to translate written words in real time -- just hover the phone over any sign/menu/information.
This isn't new BUT TripIt organizes travel so you can visualize your entire trip. If you're doing multiple legs, it can be really helpful. It's also alerted me to a delay before the airlines have in the past and it syncs with Concur.
What I like about Flip is the widget you place on your screen. Nothing complicated, just touch the widget, drop in your price and it does the calculation. Android only. Iphone users I think XE Currency is your best bet.