Power View, formerly known as “Project Crescent is the interactive data exploration, visualization, and presentation tool for end users shipping with Reporting services in SQL Server 2012 for easy to use ad-hoc reporting and data exploration.
Reports can be created from data in PowerPivot workbooks or tabular BI Semantic Models deployed to SQL Server 2012 Analysis Services. Power View runs in a browser, powered by SharePoint Server 2010, and enables users to present highly interactive visual presentations.
This video is a great intro: http://channel9.msdn.com/posts/SQLShorts-SQL-2012-Power-View-on-SharePoint-2010
For a deep-dive into the overview, see the TechNet page :http://technet.microsoft.com/en-us/library/hh213579(SQL.110).aspx#PresentationReady
