1) Download RootPack.zip (10.91MB) below
2) Copy upd.zip to your SD Card
3) Open odin, import the file I8160XXLD8_ready_to_root_ANT.tar.md5 as a PDA.
4) Boot your phone in download mode (hold vol down + home + power)
5) Hit start on odin
6) Once odin has finished, boot your phone into recovery mode (vol up + home + power)
7) Select update from SD Card, select upd.zip and flash it.
8) Done! Boot up your phone and you have root! Use root checker to verify root access.
The RootPack.zip contains everything needed to root the phone, including the original firmware should you have problems.