Scrolling/Gestures - Trackpad will scroll up and down with a reverse action from what you are used to with a computer. The scrolling and gestures are customizable, see the Trackpad box to the right.
Launchpad - displays every application, see the Tips and Tricks box.
Applications may be viewed in full screen using the arrows in the upper right hand of the window, mouse to the top of the screen for a roll down menu that will allow exiting from full screen. See below for more information.
Auto save, Versions, Resume - Saving is automatic and previous versions may be viewed, see the Saving Documents box below.
Mission Control - Combines Exposé, Spaces and Dashboard screen management functionality. See Mission Control box to the right.
Airdrop - Simple sharing between computers. See the Tips and Tricks box.
Mac App Store is now built in.
This link from Apple Support provides a very good explanation of Auto-Save, Versions and Duplicate. http://support.apple.com/kb/HT4753
For a different explanation of the changes involved with Auto-Save, Versions and Duplicate look at this article from Macworld. http://www.macworld.com/article/1161192/lion_versions_auto_save_resume.html
If you just can't get used to Duplicate instead of "Save As" this OSX Daily post will give you a work around. http://osxdaily.com/2011/11/30/how-to-save-as-mac-os-x-lion/
View Applications Full Screen
This link from Apple Support contains directions for going full screen and back. http://support.apple.com/kb/PH4530
This link from Apple Support provides videos and step-by-step instructions with photos regarding tapping, scrolling, pinching and swiping on the Multi-Touch trackpad. http://support.apple.com/kb/HT4721
This article from Apple Support gives an overview of Mission Control. Look to the right under related articles for more details. http://support.apple.com/kb/HT4689
PC Magazine provides instructions for creating multiple desktops with different backgrounds. http://www.pcmag.com/article2/0,2817,2388803,00.asp