it depends on who your provider is, but normally you got under messages and then scroll down till you get to voice messages.. or if you are with T-mobile you can hold down the 1 key on your keypad to call the voice mail service.
Go to the top mail, click on it then hold down the shift button, while scrolling down to the bottom of all the mails, (Keep that shift button down) when at the bottom all e mails should be highlighted then right mouse click and delete. Done
First, you click on the Pokemon that is holding the air mail then,there should be a littile box go down to the word mail click on it then it will say read or take select take then it will say send your removed mail to your PC select yes then your done!!!!!!(: