When setting up your brand new iPhone, ofcource you wanna check the Visual Voicemail feature.
The moment i start this feature the first time, I was asked to give a voicemail password.
I was wondering where this password is used for.
The answere was easy.
If you want to check your voicemail from another phone you need this password.
Call your own phone number. As your greeting plays, enter *, enter your voicemail password followed by #, then follow the voice instructions.
Pretty easy, but usefull to know (and to remember 
)
Check for more voicemail settings Apples website: