Sure. .po files are translation files used by many applications (mostly gpl/freeware/shareware). It's used for translations of web apps too. It has translation of whole sentence/question and not only one word, which makes translated version easier to read.
I don't think there is an editor, however .po files you edit using desktop tools will work for Windows CE GPL applications, if that's what you're after.
Thanks, I thoght about translating in the train as I have 6 hour trip and why waste time if there is something ppl want? I suppose I will have to use laptop.