Many people feel "lost" when moving from previous versions of Microsoft Outlook to the newest Outlook 2010. Finding a feature you know exists, but was "moved" can be frustrating at first.
Similar to Microsoft’s Outlook 2010: Menu to ribbon reference workbook; the How to-Outlook website has a "Where do I find that feature?" guide, specifically for people upgrading to Microsoft’s Outlook 2010. Their guide contains a list of the most commonly used features and options that have been shifted around or renamed between Outlook versions. (Thanks Ilse)