In addition to the address supplied by Eric Hellman there is

http://rzblx1.uni-regensburg.de/ezeit/

This is a site in Germany (you can change the default interface to
English)which lists on-line articles and indicates those that are free and
those that you have to pay for.

_____________________________________________
Carol Bream
Réseaubib Service Manager
Central Library
European Commission
B-1049 Brussels

* +32-2-295.29 80 (direct phone)
* +32-2-299.98.17 (fax)
http://europa.eu.int/comm/libraries/index.htm