This quasi-experimental study examined the effects of online professional development in technology with Virtual Communities of Practice (VCoP) on teachers' attitudes and content integration. This research study took place completely online. Over a period of nine months three cohorts of educators from diverse backgrounds and geographical locations took part in a six week course of online professional development using resources designed by the researcher. The comparison group in each of the three cohorts accessed content via a course website and corresponded with the researcher only. The treatment group in each of the three cohorts accessed content via a course wiki and corresponded with the researcher and with each other as members of a VCoP. Both groups received the same professional development content. Three instruments were used for data collection online: A researcher designed demographic Survey, the Teachers' Attitudes Toward Computers (TAC) and the Levels of Teaching Innovation (LoTi), including Computers for Instructional Purposes (CIP) and Personal Computer Use (PCU) subscales. Informal learning, knowledge sharing, and creation are critical if teachers are to practice life-long learning. As technology develops and budgets shrink, the potential for free and low cost professional development with flexible access and just-in-time availability should be investigated. This study proposed to extend knowledge on Virtual Communities of Practice as potential resources for the pursuit of sustained informal professional development to support teaching and learning practices in the context of curriculum and a supportive environment. Findings indicated that teachers' attitudes toward computers on the subscale of interest could be predicted by technology professional development coursework. Professional development in technology with VCoP and without VCoP were determined to be of equal value. Teachers who received professional development online with Virtual Communities of Practice demonstrated the highest level of technology integration with classroom practices. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]