The University of Southern California’s Center for Muslim-Jewish Engagement has an online resource for Jewish and Islamic religious texts.
Source guides on Shariah
Organizations on Shariah
The Sabr Foundation, a nonprofit religious educational group offers this history of Muhammad.
The Islam Project is a multimedia effort aimed at schools, communities and individuals who want a clearer understanding of Islam. The project is partially funded by the Carnegie Corporation. It offers this background on Muhammad.
The Macdonald Center for the Study of Islam and Christian-Muslim Relations at Hartford Seminary in Connecticut has this page with links on Muslim-Christian relations.