Assuming you can't get the company directory, you can try a couple of things:

1) Make friends with the company HR Department, then ask for the names of those being laid-off (slim & none chance) or offer to conduct seminars on the options available for their retirement accounts, now that they're being laid-off. Even better, have guest speakers at your seminar; such as, someone from the Dept. of Labor, maybe a shrink to talk about the stress about being laid-off and how to handle it, someone from a technical school to talk about job retraining, etc.

2) If HR blows you off, you can always advertise your seminar in the paper, directed toward those who are laid-off. Expensive yes, but it may be effective.

3) You might also try the labor union for access to those laid-off, assuming the employees have one.

4) Call your favorite wholesaler(s) and ask them for some ideas.

5) Sponsor or co-sponsor a jobs fair for those laid-off.

The important thing to keep in mind is that every other broker in your area, is thinking the same thing as you. That's why you need to be creative with your approach and your seminar, if you have any hope of standing out from the pack.

There are plenty of companies that sell corporate directories, I would google the name of the company along with "leads, corporate directories, etc."  If I come across a lead provider I will post it, Happy Hunting