Manufacturing organizations are the best places to look. Join or participate in some good manufacturing associations, and look for referrals from people in those groups.
In the meantime, Google is a great place to start looking for companies. I just did a Google search on "manufacturer of lanyards" and received 3,450 hits on that one product alone.
Question added to topic Starting a Business • November 12, 2008
Where can I find manufacturers for my products?
I am looking for manufacturers to make several small items such as lanyards for IDs, retractable key/ID holders and penlights. I am trying to find contact information for manufacturers that may be able to help, and I have no idea where to look.