OT: Mobile phone accessibility guidelines

Dear all,

I am currently looking for some guidelines / regulations / guiding 
documents for accessibility with respect to mobile phones. Does anyone 
here could send me some links or ideas where to look? Please send via PM.
I am interested in anything you can give me - from all over the world. 
So far I was not very successful ...

Thanks in advance for your assistance!

Solong

     Ginger