Four Articles on Old Stock Certificates:
Find the Value of an Old Stock Certificate
Stocks From the Attic Are your decades' old stock certificates worth anything?
Four Companies that Research Old Stock Certificates and their Value:
The SEC's advice on Old Stock Certificates
http://www.sec.gov/answers/oldcer.htm
A Market For Old Stock Certificates
Even though the Company may be out of business, there may very well be value in the old stock certificate. The hobby of collecting old stock certificates is called Scipophily and the following site brings together buyers and sellers.
http://www.scripophily.com
http://www.realstockcertificates.com/