Why not paint stucco?.... Could not have said it better myself... Doityourself.com
Got a half-hour? Very thorough exposition of everything you might want to know about traditional three-part stucco.
Inspectors Journal Online - Experienced perspective on paint over cement stucco.
Thoughful article on maintenance of exterior stucco and dealing with certain kinds of staining.
Fellow Cement-Based Stucco Care Contractor, in San Diego adresses the question of Why you should not paint stucco.
Builder also adressing the issue of Painting Stucco.
Article in This Old House about a few issues with Painting Stucco.
Stucco Manufacturers Association – Three coat stucco maintenance guidelines.