Collection of some cheat sheets

http://packetlife.net/library/cheat-sheets/

http://serverfault.com/questions/31495/cheat-sheets-for-system-administrators

http://www.cheat-sheets.org/

http://mj12net.org/index.php/system-administrator-interview-cheat-sheet.html

http://devcheatsheet.com/

http://blogs.msdn.com/b/powershell/archive/2007/01/25/powershell-cheat-sheet-redux-the-pdf-version.aspx

http://www.newdrp.com/Posters/ToolsAddonsUtilities/tabid/71/Default.aspx