Concepts and documentation - https://powerbi.microsoft.com/en-us/documentation/powerbi-service-basic-concepts/
Guided learning - https://powerbi.microsoft.com/en-us/guided-learning/powerbi-learning-0-0-what-is-power-bi/
Youtube video - https://www.youtube.com/watch?v=nOaeJ9D_9D4 (there are several more available online for specific topics within powerbi)
Free Microsoft Training - https://mva.microsoft.com/product-training/power-bi#!prodv=Power%20BI%20for%20Office%20365&lang=1033
Free Microsoft Getting Started - https://docs.microsoft.com/en-us/power-bi/guided-learning/gettingstarted
Free Microsoft Getting Data - https://docs.microsoft.com/en-us/power-bi/guided-learning/gettingdata#step-0
Free EdX Analyzing and Visualizing Data with Power BI - https://www.edx.org/course/analyzing-and-visualizing-data-with-power-bi
Microsoft Consulting Services - https://appsource.microsoft.com/en-us/marketplace/consulting-services?country=US&page=1&serviceType=workshop&product=power-bi