1. ExcelExposure.com – A free online Excel training class designed to help you learn more about the features and functionality of Microsoft Excel 2010.
2. Chandoo.org – A blog about learning and sharing Excel tips, charting tutorials, visualization ideas, and downloadable Excel tutorials.
3. ThinkTutorial.com – A plethora of Microsoft Excel tutorials.
4. GCFLearnFree.org – Learn basic Excel tips.
5. ExcelRibbon.Tips.net – Tips and ideas designed specifically for users of Excel 2007, Excel 2010, and Excel 2013.