How do you switch from Windows to the Apple OS? There is a keybord command which I have forgotten.

if in Windows o/s, this is the command line option. The Bootcamp gui

Note: This command requires Boot Camp 3.0 or later (beginning with Mac OS X v10.6 Snow Leopard).

1. Boot the Mac using Windows.
2. Click on Start.
3. Click on All Programs.
4. Click on Accessories.
5. Click on Command Prompt.
6. Type in the following command:
   c:\progra~1\Bootca~1\bootcamp.exe -StartupDisk "Mac OS"
   Shutdown /r /t 0
7. The computer will restart into Mac OS X.

If you have other Mac O/S version or boot camp version, the process may be different.

Google is still your friend.

link: http://support.apple.com/kb/HT3802

Here's a couple of links that might give you some easier methods to switch between Mac and windows:

http://hints.macworld.com/article.php?story=20080417063522778

and

http://www.nzmac.com/15-leopard/58-quickly-restarting-a-mac-to-run-windows-under-bootcamp-and-vice-versa.html

while in windows.... lower right corner....bootcamp icon....click....select restart in Mac OS