I know i'm probably being a bit thick here, but i'm going to LA this evening and although i've got my phone enabled to work over there, i want to turn off voicemail as it would cost a bomb for any poor sap who calls me (if i dont answer and they get through to my voicemail) and for me to pick up my messages. So how do i set my phone just to ring off, instead of going to voicemail after x amount of rings? 
Thanks.

Thanks.