This should be pretty simple. You're only going to need a few things and this will have no effect on the data that is on your phone.
First you'll need Odin. It is an application you use to flash, or install things on your phone directly.
That can be found
HERE
The next thing you'll need is CWM (Clockwork Mod Recovery). This replaces the stock recovery mode on your phone to allow you to install zip files from your SD card, as well as make backups, restore, clear caches, data, etc.
That can be found
HERE
And finally, the Superuser + Busybox files needed for root access. This will be a zip file which you will install with CWM once we get that on there.
That can be found
HERE
Ok, once you have all 3 files downloaded on your computer, leave Odin3_v1.3.exe and the CWM3_Voodoo.md5.tar files somewhere you can find them, and put Busybox+SU-Edify.zip on your phone's SD card.
Now you're going to install CWM on your phone. To do this, power your phone off and remove it's battery. Next plug your USB cord from your computer into your phone. Then hold the volume down button on the phone until you see a big yellow triangle and "Download" appear. This is the mode you put your phone in to use Odin.
Now that you're phone is in download mode, launch the Odin file on your computer. You'll notice a row of 8 white boxes at the top, and 8 smaller white boxes blow that in the ID:COM section of Odin. One of the smaller boxes should be yellow and say COM with a number. This shows that Odin has made a connection to your phone in Download mode.
Next, click the
PDA button in Odin. DO NOT USE ANY OTHER BUTTONS! This will pop up a window where you can browse to the CWM3_Voodoo.md5.tar file on your computer. Once you select it with Odin, hit Start.
It should only take about a minute or less you'll see the Message section of Odin displaying its progress along the way. Once it is complete, your phone will go black and Odin will say PASS in a green box at the top. From here you can close Odin and unplug your phone from USB.
Now you're going to boot into the CWM recovery you just flashed. Reinsert your battery, then hold the Volume +, Volume -, and Power keys all together on your phone until you see the Samsung logo. Once that appears, you may release the keys while it loads.
Once in recovery, you will see many options in red text. To navigate here, you use the volume rocker to go up and down, and the power button to select. Go down to "install zip from sdcard" and select it. Next, go down again to "choose zip from sdcard" and select that. From here, you need to navigate to the Busybox+SU-Edify.zip you put on your SD card in the beginning. If you just put it on the root of the card (not in a folder) it should be at the bottom of the list.
When you select it you will be taken to a confirmation page with many no options, and one yes. Scroll to the yes and select it. This will start the installation of the root required files. Once it is complete, scroll to the bottom of the list you see to Go Back until you're at the main menu of CWM. This first option in the main menu is "reboot system now". Select that and your phone will start up. Once it is loaded, you should now see a Superuser icon in your app drawer and have the ability to give apps that require it root access.
Congratulations. You are now rooted and know how to use Odin and CWM for the future.