Al Waraq | http://www.alwaraq.com/

Al Waraq is a broad resource for students and teachers about Arab culture, including art, literature, folklore, and religion.  It includes both text and audio materials, and access to several famous works of literature in Arabic.
Somewhat difficult to navigate, requires registration.

Arabic Poems | http://arabicpoems.com/

A collection of poetry in Arabic organized by period (Jahiliyya, Islamic, Abbasid, Andalusian), audience (children’s), language (FusHa and Ammiyya), and other groups of interest (women authors, poetry about Lebanon).  The poems are posted by users under these broad categories.  This is an excellent resource for primary sources for students and teachers.
Good collection, easy to navigate by category.

Arabiyat | http://www.arabiyat.com

A website and magazine aimed at Arab women and young women.
Organized, with interesting articles.  Teachers may want to preview for content.

Lakii | http://www.lakii.com

Lakii is a website and network geared towards women, including sections on beauty, cooking, lifestyles, and raising children.
Harder to navigate than "Arabiyat;" teachers may want to preview for content.

Moheet | http://www.moheet.com/

This site provides links to information about Arab countries, contemporary events and issues, as well as to their history and art. Useful for intermediate level students, materials can be adapted for use in the classroom.
Easy to navigate, the weather page is a good resource.

Nesnas | http://www.nesnas.com/

A directory and networking website in Arabic, it has comprehensive links to the Arab press, as well as personal and social networking areas.
Similar to Yahoo!, Nesnas is most useful for its links to the Arab media in addition to using short clips about various topics for comprehension exercises and reading.

Sahafa | http://www.sahafa.com/

Links to newspapers and news magazines in Arabic grouped by country, including the United States and the United Kingdom.
Easy to navigate, links are more useful than the "News" portion of the website.