Doesn't work. Says invalid option.
How Do I Check Cell Phone Voice Mail From A Land Line Using An AT&T Go Phone?
Dial your cell phone number, then when you start hearing your voicemail message, press the " * " button, it then prompts for your password, enter that and you are in.
Call your cell phone number, let it ring until your voicemail message comes on, press the # sign, it'll ask for your password, proceed like you are checking it via your cellphone.