1. Download Redsn0w... To find the download files just do a google search for Redsn0w 0.9.9b9 for either Mac or Windows
2. Connect your iPhone to your computer.
3. Run Redsn0w once you have it downloaded... If you are on Windows Vista or Windows 7 then right click Redsnow and set compatibility to windows xp (service pack 2) and then you can run the application as a administrator.
4. Once Redsn0w is open Hit "jailbreak" and then enter DFU mode on your phone by doing the following on your phone....
- hold down the power button for about 3 seconds
- now while continuing holding down the power button, start holding the home button and keep holding both of the buttons for about 10 seconds
- now let go of the power button and continue holding down the home button for about 20 seconds ... Make sure you are holding it for 20 seconds even if the screen starts doing some thing( Count 20 seconds )
5. Once this is done select install cydia and any other things you want... do not select install custom bundles
4. Wait for it to finish and reboot... this can take a while
5. Close out of Redsn0w... This is an important thing to do.
6. Open Redsn0w and go to “Extras”
7. Hit “Just boot” and enter DFU mode again by following the instructions in step 4