On July 16, 2012, Office 2013 Preview was released to the public (download).  Excel 2013 now includes a lot of the SQL Server BI components directly in the initial install, as well as enhancements made to the business intelligence (BI) capabilities in Excel.  Here are the details:

UPDATE: On 10/31/2012, the RTM of Office 2013 was available on volume license customers.  It will be available to the public Q1 of 2013 (likely in January).

• Much of the core PowerPivot functionality, including the xVelocity in-memory analytics engine, has been built into the Data Model in Excel.  This brings the capability to import millions of rows into a table and create relationships between the tables, including disparate data sources.  When you add a connection, you can now choose to import multiple tables
• The PowerPivot add-in is now by default installed together with Excel.  All you need to do is enable it in the options.  There are a few new features in there like Categorizations and new datamarket integration
• Pover View has now also become an add-in in Excel so you can now work with Power View offline in Excel.  It can be either connected to the Excel data model or to an external Analysis services instance.  SharePoint is not required.  Power View also supports some new visualizations like charts, pie charts, themes and more
• Quick Explore, Trend Charts, Quick Analysis and Flash Fill: Improve productivity by easily shaping your data with Flash Fill; using Quick Analysis to preview and apply conditional formatting, suggest and create charts, PivotTables, and tables; and use Quick Explore to easily navigate multidimensional and tabular data models and create Trend charts to analyze information over time.
•  Interact with Excel pivot tables on the web and share with anyone.  See Using Pivot tables in the Office Excel Web App

More info:

What’s New in Excel 2013 Preview

Excel 2013’s Impact for BI Users

Power View meet Microsoft Excel 2013, Power View meet Microsoft Excel 2013 Part 2

What’s New in Office 2013 BI – (Part 1 – Personal BI with Excel), What’s New in Office 2013 BI: (Part 2 – Power View Enhancements), What’s New in Office 2013 BI: Part 3 – Improved Productivity, What’s New in Office 2013 BI: Part 4 – New Features in Excel Web Reports

Excel 2013 and BISM Multidimensional, Power View in Excel 2013 Part One: Pie Charts, Power View in Excel 2013 Part Two: Maps

Introducing Excel 2013

Microsoft Business Intelligence in Excel 2013, SharePoint 2013 and SQL Server 2012 SP1

Announcing Microsoft SQL Server 2012 Service Pack 1 (SP1) Community Technology Preview 3 (CTP3)

What’s new in Power View in Excel 2013 and in SharePoint 2013

Creating Maps in Excel 2013 using Power View

Office 2013 Preview – Enabling PowerPivot in Excel

Excel 2013: Complete and powerful self-service BI tool

What Are The Big Changes In Excel 2013 For BI?, Building a Simple BI Solution in Excel 2013, Part 1, Building a Simple BI Solution in Excel 2013, Part 2

Going All In with Excel 2013

PowerView with SSRS 2012 Native mode and Excel 2013

Why SharePoint 2013 (ECS) is great for Multi dimensional!

Office 2013 Store and BI

Creating your first PowerPivot Workbook in Excel 2013 Preview

Excel Graduates to a Complete and Powerful Self-Service BI Tool

Power View Map in Excel 2013 Preview

Excel 2013 BI versus SSRS 2012

Excel 2013 – Implications for PowerPivot and Excel Data Import Users–Part I

Excel 2013 – Implications for PowerPivot and Excel Data Import Users–Part II

Excel 2013 Business Intelligence New Features –Deep Dive – I

Excel 2013 Business Intelligence New Features –Deep Dive – II

Intro to Power View for Excel 2013

Some thoughts on what Office 2013 means for Microsoft BI

BUSINESS INTELLIGENCE POWER HOUR #2 – POWER VIEW IN EXCEL 2013

Introduction to the Data Model and Relationships in Excel 2013

Using Microsoft Office 2013 for Business Intelligence

Excel 2013 – Microsoft’s BI Tool and Why You Should Use It

PowerPivot vs. Power View: What’s the Difference?