Hi!This a full explanation to installing whited00r on you iPhone.
[Pictures below] Sorry guys, I don't have much experience whit MACIf your iPhone is not unlocked, you should download the normal firmware,(either full or lite) and if it is unlocked, download the unlocked firmware,(either full or lite).
Want To Jailbreak your iPhone?Scroll down! Step 1: Download the custom firmware, either normal or unlocked.
(Links below)Step 2: Put your iphone into DFU mode.If you don't know how to enter DFU mode, scroll down below.
Step 3: iTunes will display a message saying you have to restore before you can use this iPhone. For a mac,hold down alt and for windows,hold down shift and click restore.
Step 4: Navigate to the whited00r firmware which you downloaded.
Step 5: iTunes shall do the needfull now. This could take upto 5 or 10 minutes.
Step 6: If you get any errors,they shall be
listed below,along with a fix.
Step 7: Your iPhone should now be booted into whited00r firmware.
Step 8: On iTunes,
set up the phone as a NEW one,not a backup, or else, you may experience
errors.
MULTITASKING:Once you double tap the home button, you should get the multitasking dock.If you do not get the dock, you may have not set up the phone as a new one, or do a hard reset twice.To do a hard reset twice, hold the power and the home button together. You should get a black screen. Keep holding till you see the apple logo.
Folders:To make a folder, make the app wiggle(hold on the app) and drag it into another. You should now get a folder. To rename the folder, click on it and hold an app(make it wiggle) you should now be able to type a new name. If you get a message saying "Folder limit reached, you have reached the maximum of 99 Folders, that's quite an achievement. seriously!" you probably reset all settings. To fix this, you have to restore. And remember to start a new phone and reboot twice!
iTunes ErrorsIf you get an iTunes error 1600, download iReb(Link below) and follow the instructions. If you are on a mac, download redsn0w, the mac link below. Follow the on-screen instructions and tick "just boot in pwned dfu mode now" and done! you can now install whited00r firmware.
If you get 2003 error in extraction of iPhone software, plug out and plug in your iphone again.
How to jailbreak your iPhone
You should be running iOS 3.1.3. Download iOS 3.1.2 from the link below.
I recommend using redsn0w(thats what I use)Download redsn0w from the link given below. Unzip Redsn0w and open it.You should be running firmware 3.1.3.Once you open Redsn0w,it will ask you to point it to your existing firmware. POINT IT TO iOS
3.1.2.Yes,make no mistake, point it to the 3.1.2 folder, and you should be running 3.1.3. Follow the on-screen instructions, and once its over, your iPhone will be jailbroken!(Whoo-hooo!)Sometimes, the iphone may get a whited screen and redsn0w might get stuck. Not to worry, just start over. An easier way to jailbreak, would be with blackra1n, just a click and all jailbroken(I would still recommend redsn0w). For mac, pretty much same, follow the instructions.
Blackra1n method: Download blackra1n from the link below. Open blacksnow. You might get the error saying that some dll was not found(sorry, I dont remember the error) If you get the error, cut blackra1n and put it into C:\Program Files\Common Files\Apple\Apple Application Support. Now open it, it should work. Connect your iPhone to the computer, and click "make it ra1n" and wait for it to finish, and done!(I still recommend redsn0w)For Mac, it is the same.
Some errors I experiencedIf you see that there is no contacts, calendars and mail, you have probably kept the app "Contacts" and "Mail" in a folder. If so remove these from the folder. If you want to keep them in folders, is to modify your Settings-iPhone/Settings-iPod.plist in /Applications/Preferences.app and remove the lines that are similar to
<key>requiredCapabilities</key>
<array>
<string>com.apple.mobilemail</string>
</array>
remove those lines, and it will show up always.

How to enter DFU:
(Use a clock if you can't count properly)Connect your iPhone into the computer first!. Turn your iPhone off. Hold the power button for 2 seconds. Now hold down the power and the home button for 10 seconds. Release the power button and hold down the home button for 15 seconds. If you get a picture of a USB pointing to iTunes, then attempt entering DFU mode again.
Speeding up whited00r : For this, the latest whited00r firmware has a ./Configurator. Check out
http://www.whited00r.com/?page_id=493 and
http://www.whited00r.com/?page_id=532You could also search the forum for more speed ups.
Download links
Whited00r firmware: Please choose your model.
http://www.whited00r.com/firmware-download-2iReb:
http://ih8sn0w.com/index.php/products/view/ireb.snowRedsn0w:
http://www.mediafire.com/?5iokykm3mttRedsn0w
(MAC):
http://www.2shared.com/file/11324354/304db1c3/redsn0w-mac_094.htmliOS 3.1.2:
http://www.iclarified.com/entry/index.php?enid=750Blackra1n:
http://blackra1n.com/ Here are some pictures..
It will show you the DFU process and once you get the error, open iReb.
Still need extra help? Feel free to ask, leave your question in the comments and I will try my best to help you.
HAPPY TO HELP!
Enjoy
Approved By JustinCase