Switching Between Windows

In Windows it's really easy to just use alt+tab to switch between all of your open windows. On your Mac it is a little bit different, it's split into two different commands.

⌘+tab switches between open applications
⌘+` (that's the tick above the tab key, not an apostrophe) switches between windows of a specific application

Hiding Windows

In Leopard if you want to minimize a window you can double click on the title bar of that window and it will minimize into the Dock as you probably know. If you want to hide the current window but don't want it showing up in the Dock you can type ⌘+h. The window will be hidden and you can bring it back by clicking on that program's icon at the bottom of the page.

Watch this screencast and you'll see what I'm talking about...