This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
Depends on what platform you wish to do it on. Ona unix/Linux system use gunzip and then tar as described above. On a Windows system, the easiest way is to open the file with WinZip, which understands the format and can extract it to a directory of your choosing.