Answering myself:
As for multi-language support, I will do the following as a first step:
- I will leave the buttons all in english only; it is just to much work for this tiny tool to have this all dynamic.
- The help will be available in different languages, referring to the english buttons.
-As help format I will use RTF, so I won't have to deal with unicode in my tools.


edit:
Forgive me for thinking out loud....
I changed my mind. RTF is nice and fancy and allows coloring, but I'd rather go with pure stuff.
From the next version on all my tools will be UNICODE aware. I still will keep only english for the buttons and menues for the time being. But the help text will be unicode and available in multiple languages.
If anyone could send we a unicode text file in some asian or eastern language it would be great to test.