Redsn0w is very simple to use, just update your device to 4.3.1, then open redsn0w. It will prompt you to find the ispw file, which, if you updated through iTunes, can be found in users/yourname/library/itunes/iPod Software Updates. It will build a custom ispw for you, and, after following the directions to put your device in DFU mode, you just have to sit back and watch your device be jailbroken.
The official version of Redsn0w can be downloaded here.
If you having trouble finding the right software to jailbreak with, try this interactive guide.
*Note: The Real Mac Genius.com does not condone illegal uses for jailbreaking (i.e. installing cracked apps), nor is responsible for any damages or loss of data that may be caused by jailbreaking.