Background/Question/Methods: Project BudBurst (www.budburst.org) is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events that raise awareness of climate change, and create a cadre of informed citizen scientists. The goals of Project BudBurst are to 1) increase awareness of phenology as an area of scientific study; 2) increase awareness of the impacts of changing climates on plants; and 3) increase science literacy by engaging participants in the scientific process. We addressed these goals by exploring how citizen science programs such as Project BudBurst can provide the opportunity for students and interested laypersons to actively participate in scientific research in a meaningful way. To determine the efficacy of extensive, Internet based citizen science programs, Project BudBurst launched an entirely Internet based pilot program in the Spring of 2007. Specifically, the Web based project sought to design and assess an education and outreach approach that supported data collection and entry. Participants were asked to observe and record the timing of phenological events of wild and cultivated plant species found across the continent. For the first observational season (April through mid-June 2007) this on-line educational and data-entry program engaged several thousand participants of all ages and walks of life in recording the timing of the leafing and flowering of over 100 easily identifiable, broadly distributed plants. Results/Conclusions: Programs such as Project BudBurst are important not only from an educational perspective, but because they also enable scientists to broaden the geographic and temporal scale of their observations. Review of the data submitted by participants suggests that extensive, Internet based citizen science programs are effective in education and outreach endeavors. As a result of feedback from the pilot effort, an enhanced and expanded Project BudBurst has been launched for the full growing season of 2008.