The Microsoft Office website now has some books online resources for Power BI.
- Power BI Getting Started Guide : http://office.microsoft.com/en-us/office365-sharepoint-online-enterprise-help/power-bi-getting-started-guide-HA104103589.aspx?CTT=1
- Power BI Overview and learning Resources : http://office.microsoft.com/en-us/office365-sharepoint-online-enterprise-help/power-bi-for-office-365-overview-and-learning-HA104103581.aspx?CTT=1
- The Data Management Experience : http://office.microsoft.com/en-us/office365-sharepoint-online-enterprise-help/data-management-experience-in-power-bi-for-office-365-help-HA104079156.aspx
These will be a really valuable resource if you want to learn more about our new cloud-based BI offering.