If you are a German, I don't have to tell you what the Leo online Wörterbuch is, if you aren't - it's the German free online dictionary for German/English, German/French, German/Italian and German/Chinese which started in the early 90s as an online catalog (LEO = Link Everything Online) by the University of Munich. While Leo isn't linking everything online anymore, it's the best available online dictionary in Germany and so far, Leo offered a pretty good mobile device interface in addition to its standard PC browser interface. However, now Leo added a couple of stand-alone applications to its portfolio which makes the use even more convenient.
For Google's Android and Palm's webOS smartphones, Leo just released two programs which still use Leo's online database but not requiring the use of the mobile web browsers anymore. Furthermore, the mobile clients feature German/Russian translation which isn't (yet) available online.
Developed by users (external developers) or by members of the LEO team, both, Leo Wörterbuch for Google Android and Leo Wörterbuch for Palm webOS are available free of charge from the respective app store. The benefits of the applications include easy access to the dictionaries and ease of use thanks to functions and features specifically customized for the different devices. Unfortunately, the user interface is German only, so it might not help you for your next trip to Germany.
Windows Mobile and iPhone users can still use the mobile web site of Leo's online dictionary.
Cheers ~ Arne