A 5-year study, conducted in two schools on the Texas-Mexico border, is investigating the effectiveness of peer coaching as a professional development strategy for teachers in two-way bilingual education programs. A group of 24 teachers, half bilingual and Hispanic and half monolingual and Anglo participated in the study. For each, classroom ethnographies were compiled after classroom observation, and teachers were videotaped at random times during classroom teaching. Six teachers were observed all day for a period of one week. In addition, teachers responded to a questionnaire on teaching practices, team teaching experience, and perceived problems and successes. Professional development sessions, during which the teachers acted as peer coaches, were also videotaped and ethnographies were developed for them. Ethnographies were analyzed for code switching, instructional patterns for each language, social/power relationships, teacher/student participation structures, and identification of particular discourse forms. The methods were found to be effective in focusing on the quality of student participation patterns, level of learning quality in each language, time and status given to each language, and teachers' professional development needs. (Contains 39 references.) (MSE)