These essays and articles are free and provide a strong introduction to the broad possibilities of cooperatives and the solidarity economy.
Basic Introductions to Worker Cooperatives:
What Is a Worker Cooperative?
Cooperativization as an Alternative to Globalizing Capitalism
The Emilian Model - Profile of a Co-operative Economy
Centers, Institutes, Think Tanks, Publications
Grassroots Economic Organizing Newsletter
British Columbia Institute for Co-operative Studies
Ohio Employee Ownership Center
University of Wisconsin Center for Cooperatives
Community-Wealth.org
Portal de Economica Solidaria
OURbiz
The Solidarity Economy:
Solidarity Economics
Strategies for Building New Economies From the Bottom-Up and the Inside-Out
Solidarity economics
Participatory Democracy in Venezuela
Dual Power in the Venezuelan Revolution
Reflections on Venezuela’s Bolivarian Revolution and its Solidarity Economy
Movements of Resistance in the Americas
Some Theory:
"Today's Haunting Specter (Or What Needs Doing)" - Great piece from Rick Wolff, an economist at the University of Massachusetts-Amherst, from the Monthly Review of June'07. He discusses the weakness of the European social democratic project (rooted in a strong welfare state) and proposes another direction for the European left. This direction would be based in direct appropriation of the surplus of their labor- meaning democratic management principles and worker ownership of firms.
"French Election's Deeper Meaning" - Another piece from Rick Wolff in May'07. More in depth discussion of the crisis of the European left and the possibilities for building a new movement around worker control.
Cooperative Games and Cooperative Organizations
David Ellerman's homepage -David Ellermen has written for years on democratic enterprises and labor-owned/managed firms. His website includes a good selection of focused discussion on the topic. See especially his section The Firm: Theory and Practice. He also offers several relevant books for free download.