What I think you're looking for is Kindle
default dictionaries:
http://www.amazon.com/b/ref=sr_tc_2_...6068&sr=8-2-tc
They can be a little tricky to find, unless you know what you are looking for. I would suggest you read the comments on Amazon before buying, just in case there's possible issues.
If you are planning to use a translation dictionary, I can point to an old thread if you are interested. Just won't spend time digging it up now unless you need it.
@Kumabjorn: The Kindle supports showing most western latin characters AFAIK - and I can assure you that it supports ä, ö, æ, ø and å.