How to populate DP listings—and then e-mail owners without spamming?

I have a new directory I am manually populating with listings. No wholesale scraping or .csv data dumps. I am choosing what I consider the “best” businesses in a certain demographic as a starting point for the directory.

I would like to email each listing owner and tell them that
• I have given them a listing
• I have given some of them a 90-day listing
• They may be getting email inquiries from my site visitors about products they may stock, and they can then deal directly with the buyer
• And if they like the results they get, hopefully upgrade to a paid listing. We only sell listings.

These businesses are worldwide, so they clearly come under many separate laws regarding email spam.

What are your experiences with populating your DP listings under similar circumstances? Do you always depend solely on the business owner somehow finding his listing and then claiming it? Or have you contacted owners of the businesses you list as I plan to do? Have you experienced email spam charges doing this?