Download these two files onto your computer:
CWM - CWM_Recovery4008.tar
Superuser - Superuser-3.0.7-efgh-signed.zip
Place the superuser file on your sd card. Turn off phone. Open ODIN, put phone in download mode by holding volume down button and connecting to pc with usb cable. Uncheck the auto-reboot box in ODIN. ODIN should recognize you phone and you should see a yellow com port show up in ODIN. Click the PDA button and choose the CWM file. Click start. When it finishes, unplug the usb cord, do not turn on your phone. Boot directly to recovery by holding the volume up, home, and power buttons then let go of all three the instant you see the samsung logo flash on the screen for the second time. Scroll to install zip from sd card with volume buttons, hit power button, choose zip from sd card should be highlighted, hit the power button, scroll to the superuser zip file, power button, scroll to yes, power button. When it finishes installing, hit the back button until you are back at the main CWM screen where reboot system now will be highlighted, hit the power button. Done, rooted.
Thanks Landshark!
One thing I would add is after getting the phone in download mode but before hitting start in ODIN install the battery. I had an oh crap moment when my download failed but putting in the battery took care of it.