May I first recommend looking into classes at your local Apple store? Apple offers classes and workshops for customers. These classes include a general overview showing you how to use your computer and more detailed lessons showing you complicated things you can do with your computer. Of course, I'm available too!
The most important thing is your Finder. The Finder is a visual representation of your file system. (The Finder is actually software.) It manages your files! This is what Apple has to say about Finder:
Introducing the Finder.The Finder is like home base for your Mac. Represented by the blue icon with the smiling face, it’s one of the first things you see when you start working on your Mac. It lets you organize and access practically everything on your Mac, including applications, files, folders, discs, and shared drives on your network. You can also see rich, high-quality previews of the contents of your files. The Finder takes full advantage of the advanced technologies in Mac OS X — such as 64-bit support and Grand Central Dispatch — so it responds more quickly to your actions.
You can access the Finder on your dock. Your dock is the bar at the bottom of the screen. It allows you quick access to your applications:
This is your Finder:
The sidebar on the left allows you to navigate the Finder window.
Devices is where you can access your hard drive and any external devices (such as iPods and cameras). iDisk is a remote file host. You'll need a MobileMe account to use iDisk.
Places is where you can reach your items. It lists users (parapluiesdoux), applications (your programs), downloads (downloaded files will go here as a default), documents, and your desktop (the screen you see with the background).
You can also find files and programs based on when you used it last. You can find items from today, items from yesterday, or last week.
Finder is an important part of your user experience. Make sure you familiarize yourself with it!
What is Mac OSX, Apple