Online Excerpts from Gramsci's 'Prison Notebooks'

I. PROBLEMS OF HISTORY AND CULTURE

1. The Intellectuals
2. On Education

II. NOTES ON POLITICS

1. The Modern Prince
2. State and Civil Society
 

III. THE PHILOSOPHY OF PRAXIS

1. The Study of Philosophy

There are some other writings by Gramsci online at the Marxists Internet Archive. And the entire book is online here.