Go to greenpois0n.com and download the version of whatever software you are running (like 5.1.1 or 6.0 etc...). After you have downloaded that open the folder where it is located. Double click on the first file. Then click the file that says jailbreak or has the green poison symbol. It will bring up a screen that says plug in your iPhone. Then click run
There are programs online you can google up. Just beware for once you do Apple will never give support again, but considering that there is a $20 fee to talk to someone who can help you per call it doesn't really matter.
Kid, you are going to destroy that phone before you know it. Just leave it as it is. Once the screen goes black or it locks up, dont come on Ask.com to find out what to do, just throw it in the trash at that point.