I found a cool program (haven't had the chance to try it out) that can change the creator type of text files.
Say for example that you create a file in SimpleText, but you want the file to open in
TextWrangler when you double click it. The only way to change that is to change the creator type of the file in the resource forks (which cannot be done directly, you'd need a separate program for it or use your Windows PC).
The program is called TextChanger and is free. You can get it at
barebones.com 