Question: I use netbeans 6.8 beta and when i load .sh (bash) file it's not colored at all. i can add a new file association for the .sh extension but it doesn't seem that there is a known associated mime type.

Answer: 
I have not tried this myself but you can get shell script support in Netbeans if you install the **C/C++ plugin**.
This is very odd. I have NB6.8beta installed with the C/C++ plugin. When I open a .sh file I *do* see syntax high lighting. Quotes strings show up in orange, commands are in blue.