If you're bootcamping, you may have trouble issuing some standard keyboard commands. For example, Print screen. Because there's no printscreen key on Mac.
To do printscreen, press Fn+Shift+F11
More information on other keys can be found at Apple's knowledge base: http://support.apple.com/kb/HT1167.
Disclosure: Previously this page has read "Fn+Shift+F4". I have no idea how I came up with F4. Mea culpa.