Download towelroot on your phone through GeoHot's website (You must have "Unkown Sources" checked under developer settings on your phone). You must also download Odin (on pc) and flash "I545_NC5_Stock_Kernel.tar.md5" to your phone by clicking the PDA button or AP button depending on Odin version(make sure you are in recovery mode-power off device, Hold volume down + home, then hold poweer until the screen pops up.) Then go to towelroot and press "make it rain". After rooted just flash "I545_NG6_Stock_Kernel.tar.md5" back to your phone as its more stable than the "NC5". Let me know if you have any questions or need links.