Custom Fields Question

Hi.
I want to be able to add custom fields to my blogs. Sounds simple so far. When i’ve tried it based on advice before it linked the custom fields to a users profile. I want to be able to link it to a blog in general. For instance, you set a blog name and description.. i’d like to add some fields to add say an address, phone number and email address which i can then use at places throughout the blog. I can then guide new users to complete these fields as part of their site creation.

Any pointers to plugins or tutorials gratefully received!