This would have come in so handy on so many of my travels:
iPhone/iPod touch only: Not everyone can afford to stay in four star hotels when traveling, which is why hostels are a great lodging option. Hostel Hero helps you find and book hostels in 150 countries straight from your iPhone or iPod touch.The best part about it is that you can get it for free on iTunes.
Each hostel comes with its own description (which is available in five different languages) and photos. You can also use the application's built-in Google Maps integration to help pinpoint the location of said hostel. Clicking on a select hostel offers you more details about the facilities including the above-mentioned photos and maps. More practically, the application lets you save and view the details offline, which will no doubt come in handy for more off-the-beaten-path type vacations.
To book a hostel, select the "make a booking" tab, then scroll through and choose your destination country and then city. Once you narrow down a hostel, book your stay using the app. Fair warning: To do so requires a 10 percent deposit and a booking fee to be paid in Euros, U.S. dollars or pounds. The remaining balance is paid at the hostel.