The purpose of this two phase mixed methods sequential explanatory study was to investigate factors that predict preservice teachers' intentions to use Web 2.0 technologies in their future classrooms and their ability to carry out their intentions during student teaching. The first phase explored factors based on the Decomposed Theory of Planned Behavior (DTPB) and the impact of Web 2.0 project on the DTPB factors related to preservice teachers' intentions to integrate Web 2.0 technologies in their future classrooms. The second, follow-up phase explored preservice teachers' actual practices using Web 2.0 technologies during their student teaching experiences and their perceptions of the factors that facilitated or impeded Web 2.0 technology use in a classroom environment. Surveys and interviews were employed to answer the research questions for both phases of the study. In the first phase, the data were collected via online survey (n = 189) and semi-structured interviews (n = 12). Results of a path analysis showed that preservice teachers' perceived usefulness of Web 2.0 technologies as the strongest determinant of their attitudes. Attitudes, in turn, had the strongest effect on their intentions to use Web 2.0 technologies in their future classrooms. Qualitative analysis of open ended survey responses and interview data revealed that preservice teachers considered Web 2.0 technologies useful for improving student engagement, interaction, communication, and enhancing their students' overall learning experiences by using innovative learning tools to which students can relate. Moreover, results indicated that preservice teachers intended to use mostly video editing/sharing technologies, wikis, online office tools, and blogs to improve their students' learning. Furthermore, preservice teachers' attitudes, subjective norms, perceived behavior control, and intentions to integrate Web 2.0 technologies in a classroom increased significantly after they worked on a Web 2.0 project. In the second phase, which occurred one year after the initial phase, the results of the quantitative survey (n = 14) and qualitative interview (n = 6) data showed that most (12 of 14) of the sampled preservice teachers were able to translate their intentions to actions during student teaching. Although they had previously suggested they intended to use several Web 2.0 tools (video editing/sharing, wikis, blogs, online office tools, etc.), they mostly used video editing/sharing (YouTube) within the classroom. Of the eleven preservice teachers who used Web 2.0 technologies, seven self-reported using Web 2.0 technologies as instructional delivery tools and six reported using them to facilitate student-centered learning. Most (10 of 11) of the preservice teachers' perceived the usefulness of Web 2.0 technologies, their own knowledge and skills (10 of 11), ease of use (7 of 11) and access to technology (7 of 11) as strong facilitators for their use. Two preservice teachers, who had intended to but did not to use Web 2.0 technologies, reported poor access to technology and a lack of support from their supervising teachers as impediments. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]