It depends on your voicemail and where you are, but for US Cellular, you usually hit 4, 4, 2, 1 from the main voicemail menu and this will turn "skip password" to on
It's been a while since I've been on but did want to let those that asked know, the above directions worked. Instead of it being something you add to the phone after pauses like we used to do, it is now an option in the voicemail preferences. Thanks