Howtogeek posted a Windows Users Guide to Mac OS X Keyboard Shortcuts

Keyboard shortcuts are essential for being productive on any device with a keyboard, whether its a Windows PC or a Mac. Use these keyboard shortcuts to get around your Mac more quickly. Many Mac keyboard shortcuts work just like the Windows ones but use the Command and Option keys. Other keyboard shortcuts are entirely different. Launching and Quitting Applications Spotlight Search: Press Command + Space to open the Spotlight search field. You can quickly start typing to search and press Enter to launch an application or open a file. Think of this like pressing the Windows key and typing to search and launch applications on Windows. Force Quit Applications: Press Command + Option + Escape to open the Force Quit Applications dialog, where you can forcibly close if theyre frozen. This is the Mac equivalent to pressing Ctrl + Alt + Escape to open the Task Manager on Windows. Force Quit The Current Application: Press Command + Shift + Option + Escape and hold down the keys for three seconds.

  A Windows Users Guide to Mac OS X Keyboard Shortcuts