PHP/MySql - address book

Hi, I'm trying to do a sort of address book where I'd put all information about anybody or any company from which I receive informtation (friend, people from work, hotels, places...) An entry starts with a name, then I can have any type of information. The table I'm using has a lot of fields, but I display via PHP only those that are not empty. I'm now facing a problem many must have already faced. A lot of people work for the same company, and I'd like to have a separate table or storage area to put that data, so that I don't have to write the same company addresse twice, and if that information changes, I won't have to go through ten or twenty people's entries to modify it. So how would I link a company's information to a person's entry? I know it may sound easy or ridiculous a question, but though I know HTML very well I'm still a beginner (learning on my own) et PHP and MySql. So far I have a neat rendering of the database I've created, but I feel I should look further into DB use. Software I'm using: EasyPHP (latest version) PHP 4 MySql PhpMyAdmin on Windows Me Main question, I repeat is : how would I link a company's information to a person's entry? Cheers Sébastien